ComSifter CS-8D Pro User manual
ComSifter®
protect web users now!
User Guide
Model CS-8D Pro
Version March 26, 2012 0326121500
The products described in this User's Guide are licensed products of Comsift, Inc. This User's Guide contains proprietary information
protected by copyright, and this User's Guide is copyrighted.
Comsift, Inc., hereafter referred to as Comsift, does not warrant that the product will work properly in all environments and applications,
and makes no warranty and representation, either implied or expressed, with respect to the quality, performance, merchantability, or
fitness for a particular purpose.
Comsift has made every effort to ensure that this manual is accurate. However, information in this User's Guide is subject to change
without notice and does not represent a commitment on the part of Comsift. Comsift makes no commitment to update or keep current
the information in this User's Guide, and reserves the right to make changes to this User's Guide and/or product without notice. Comsift
assumes no responsibility for any inaccuracies and omissions that may be contained in this User's Guide. If you find information in this
User's Guide that is incorrect, misleading, or incomplete, we would appreciate your comments.
No part of this User's Guide may be reproduced or transmitted in any form or by any means, electronic or mechanical, including
photocopying, recording, or information storage and retrieval systems, for any purpose other than the purchaser's personal use, without
the express written permission of Comsift.
Comsift, ComSifter, CSphrase and the Comsift logo are trademarks of Comsift, Inc.
All other trademarks or registered trademarks listed belong to their respective owners.
Copyright 2003-2011 Comsift, Inc.
All rights reserved.
FCC STATEMENT
This product has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment
generates, uses, and can radiate radio frequency energy and, if not installed and used according to the instructions, may cause harmful
interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this
equipment does cause harmful interference to radio or television reception, which is found by turning the equipment off and on, the user
is encouraged to try to correct the interference by one or more of the following measures:
Reorient or relocate the receiving antenna
Increase the separation between the equipment or device
Connect the equipment to an outlet other than the receivers
Consult a dealer or an experienced radio/TV technician for assistance
TABLE OF CONTENTS
i
Table of Contents
Table of Contents ................................................................................................................................................i
Introduction and Getting Started ..................................................................................................................1–1
Features..........................................................................................................................................................................1–1
How ComSifter Works...................................................................................................................................................1–2
Overview.......................................................................................................................................................................1–3
Internet Gateway ..........................................................................................................................................................1–3
Non-Stop Operation......................................................................................................................................................1–3
Firewall .........................................................................................................................................................................1–3
Filtering System............................................................................................................................................................1–3
Navigating Through This User Guide...........................................................................................................................1–4
Conventions in This User’s Guide................................................................................................................................1–4
Installing ComSifter........................................................................................................................................2–1
Installation......................................................................................................................................................................2–3
Security Considerations................................................................................................................................................2–3
Location/Placement......................................................................................................................................................2–3
AC Power......................................................................................................................................................................2–3
Network Connections....................................................................................................................................................2–3
Power On and Indicator Lights.....................................................................................................................................2–3
Windows 2000/XP/Vista/7 ............................................................................................................................................2–5
Making a secure connection.........................................................................................................................................2–7
Quick Start Guide...........................................................................................................................................................2–9
How will the ComSifter Connect to the Network?.........................................................................................................2–9
Do I need only one filter or multiple filters? ..................................................................................................................2–9
Do I need Proxy or Transparent Mode?.......................................................................................................................2–9
How will I identify and authenticate a user?.................................................................................................................2–9
How will the ComSifter get a list of my users?...........................................................................................................2–10
How many filters will I need?......................................................................................................................................2–10
What filter will each user be assigned to?..................................................................................................................2–10
Network Worksheet .....................................................................................................................................................2–11
Pre-Install Preparation................................................................................................................................................2–11
Installation, Phase 1, Initial Connectivity....................................................................................................................2–12
Installation, Phase 2, Determining the Authentication Method...................................................................................2–12
Installation, Phase 3, Tuning the Filters .....................................................................................................................2–12
Installation, Phase 3, Finishing Up.............................................................................................................................2–12
Authentication Methods (Quick Setup).......................................................................................................................2–13
BASIC Only.................................................................................................................................................................2–13
Prerequisites............................................................................................................................................................2–13
TABLE OF CONTENTS
ii
Quick Setup.............................................................................................................................................................2–13
NTLM..........................................................................................................................................................................2–14
Prerequisites............................................................................................................................................................2–14
Quick Setup.............................................................................................................................................................2–14
IDENTD Only..............................................................................................................................................................2–15
Prerequisites............................................................................................................................................................2–15
Quick Setup.............................................................................................................................................................2–15
IP Only........................................................................................................................................................................2–16
Prerequisites............................................................................................................................................................2–16
Quick Setup.............................................................................................................................................................2–16
Configuring ComSifter ...................................................................................................................................3–1
Configuration Overview ................................................................................................................................................3–1
Admin..............................................................................................................................................................................3–1
Understanding Modules and Categories...................................................................................................................3–1
Security Configuration ..................................................................................................................................................3–2
Login..........................................................................................................................................................................3–2
ComSifter Admins.........................................................................................................................................................3–3
Overview....................................................................................................................................................................3–3
Setting the Username and Password........................................................................................................................3–4
Assigning Module Rights...........................................................................................................................................3–4
Remote Administration .................................................................................................................................................3–8
IP Access Control......................................................................................................................................................3–8
Deny from all IP’s...................................................................................................................................................3–9
Allow from all IP’s...................................................................................................................................................3–9
Allow from only listed IP’s ......................................................................................................................................3–9
Follow My IP..............................................................................................................................................................3–9
Disable ...................................................................................................................................................................3–9
Follow the listed IP...............................................................................................................................................3–10
System Logs...............................................................................................................................................................3–11
Access Log..............................................................................................................................................................3–12
Status Messages..................................................................................................................................................3–12
Firewall....................................................................................................................................................................3–14
DHCP Non-Stop......................................................................................................................................................3–16
Duplicate IP Notification.......................................................................................................................................3–17
Security Log.............................................................................................................................................................3–18
Top Sites Log ..........................................................................................................................................................3–19
Network.........................................................................................................................................................................3–20
ADSL Client................................................................................................................................................................3–21
Dynamic DNS Provider...............................................................................................................................................3–22
Add an entry............................................................................................................................................................3–22
TABLE OF CONTENTS
iii
Create runtime program..........................................................................................................................................3–22
Update All................................................................................................................................................................3–23
Firewall Advanced ......................................................................................................................................................3–24
Overview..................................................................................................................................................................3–24
Masquerading (SNAT).............................................................................................................................................3–25
Firewall Rules..........................................................................................................................................................3–26
Create Firewall Rules..............................................................................................................................................3–27
Action ...................................................................................................................................................................3–27
Logging.................................................................................................................................................................3–27
Source Zone.........................................................................................................................................................3–28
Destination Zone..................................................................................................................................................3–28
Protocol................................................................................................................................................................3–28
Source Ports ........................................................................................................................................................3–28
Destination Ports..................................................................................................................................................3–28
Common Rules........................................................................................................................................................3–29
DNS......................................................................................................................................................................3–29
Client Email (POP3, IMAP, SMTP)......................................................................................................................3–30
FTP.......................................................................................................................................................................3–31
ICQ/IM..................................................................................................................................................................3–32
Laplink™ ..............................................................................................................................................................3–33
MSN™ Messenger...............................................................................................................................................3–34
PCAnywhere™.....................................................................................................................................................3–36
Ping and Traceroute.............................................................................................................................................3–37
PPTP....................................................................................................................................................................3–38
Telnet ...................................................................................................................................................................3–40
VNC......................................................................................................................................................................3–41
Yahoo™ Chat.......................................................................................................................................................3–42
Web Access (browsing) .......................................................................................................................................3–43
Apply Configuration.................................................................................................................................................3–45
Stop Firewall............................................................................................................................................................3–45
Check Firewall.........................................................................................................................................................3–45
Backup.....................................................................................................................................................................3–45
Restore....................................................................................................................................................................3–45
Firewall Basic (Templates).........................................................................................................................................3–46
Template 1, High Security.......................................................................................................................................3–46
Template 2, High – Medium Security......................................................................................................................3–46
Template 3, Medium Security..................................................................................................................................3–46
Template 4, Medium – Low Security.......................................................................................................................3–47
Template 5, Low Security........................................................................................................................................3–47
Network Configuration................................................................................................................................................3–48
TABLE OF CONTENTS
iv
Network Interfaces (IP Address Configuration).......................................................................................................3–48
Interfaces Active Now ..........................................................................................................................................3–49
Interfaces Active at Boot Time.............................................................................................................................3–49
WAN Interface Settings (eth0) .............................................................................................................................3–49
LAN Interface Settings (eth1)...............................................................................................................................3–50
Virtual Interfaces......................................................................................................................................................3–51
Routing and Gateways............................................................................................................................................3–52
DNS.........................................................................................................................................................................3–53
Completing the DNS/Gateway Configuration..........................................................................................................3–54
Recovering a lost IP address ..................................................................................................................................3–54
Network Utilities..........................................................................................................................................................3–55
Network Wizards.........................................................................................................................................................3–56
Static IP...................................................................................................................................................................3–57
External IP............................................................................................................................................................3–57
External Subnet Mask..........................................................................................................................................3–57
External Gateway.................................................................................................................................................3–57
Internal IP.............................................................................................................................................................3–57
Internal Subnet Mask...........................................................................................................................................3–58
Primary DNS........................................................................................................................................................3–58
Secondary DNS ...................................................................................................................................................3–58
DHCP Server for Local LAN.................................................................................................................................3–59
Firewall Template.................................................................................................................................................3–59
Non-Stop Relationship.........................................................................................................................................3–59
Non-Stop Peer IP.................................................................................................................................................3–59
Dynamic IP..............................................................................................................................................................3–60
Bridge......................................................................................................................................................................3–61
PPPoE.....................................................................................................................................................................3–62
User Name...........................................................................................................................................................3–62
Password..............................................................................................................................................................3–62
Current Network Settings........................................................................................................................................3–63
Non-Stop/DHCP Configuration...................................................................................................................................3–64
Using the ComSifter DHCP Server .........................................................................................................................3–64
Information...............................................................................................................................................................3–65
List Leases...........................................................................................................................................................3–65
Non-Stop Status...................................................................................................................................................3–67
Non-Stop Configuration (Primary)...........................................................................................................................3–69
Non-Stop Configuration (Secondary)......................................................................................................................3–71
Subnets and Shared Networks................................................................................................................................3–73
Edit Client Options ...............................................................................................................................................3–75
Address Pool in Subnet........................................................................................................................................3–76
TABLE OF CONTENTS
v
Host and Host Groups.............................................................................................................................................3–77
Starting and Stopping the Non-Stop/DHCP Server.................................................................................................3–78
Quality of Service (QOS)............................................................................................................................................3–79
Overview..................................................................................................................................................................3–79
Determining the True Connection Speed................................................................................................................3–80
Configure QOS........................................................................................................................................................3–81
Connection Speed................................................................................................................................................3–81
Queue Rate and Ceiling.......................................................................................................................................3–81
Destination Ports..................................................................................................................................................3–82
Destination IP’s....................................................................................................................................................3–82
Viewing Queue Status.............................................................................................................................................3–82
Maintenance .................................................................................................................................................................3–83
Backup/Restore..........................................................................................................................................................3–84
Creating a Backup...................................................................................................................................................3–84
Restoring the Backup..............................................................................................................................................3–85
ComSifter Status.........................................................................................................................................................3–86
Active Directory Last Resync ..................................................................................................................................3–86
CPU Load Average .................................................................................................................................................3–86
Content Filter Service..............................................................................................................................................3–86
DHCP Available Leases..........................................................................................................................................3–86
DHCP Server...........................................................................................................................................................3–86
DNS Resolving........................................................................................................................................................3–87
Hardware Health .....................................................................................................................................................3–87
Internet Connected..................................................................................................................................................3–87
Non-Stop Operation ................................................................................................................................................3–87
Proxy Server Service...............................................................................................................................................3–87
Hours of Operation..................................................................................................................................................3–87
Denied Access Page ..................................................................................................................................................3–88
Overview..................................................................................................................................................................3–88
Local Message ........................................................................................................................................................3–88
Download/Install IDENTD...........................................................................................................................................3–89
File Manager...............................................................................................................................................................3–90
Information..................................................................................................................................................................3–91
ComSifter Information .............................................................................................................................................3–91
ComSifter Release Notes........................................................................................................................................3–92
Internet Connection Test............................................................................................................................................3–93
System Name.............................................................................................................................................................3–94
System Time...............................................................................................................................................................3–95
Utilities........................................................................................................................................................................3–96
Advanced Network diagnostics...............................................................................................................................3–96
TABLE OF CONTENTS
vi
Email Notification Parameters.................................................................................................................................3–96
Restart Services......................................................................................................................................................3–98
Rebuild ComSifter Proxy Cache..............................................................................................................................3–98
Restart ComSifter....................................................................................................................................................3–98
Clear all log files......................................................................................................................................................3–98
Clear DHCP Lease Database .................................................................................................................................3–98
Filter Setup......................................................................................................................................................4–1
Filter Overview ...............................................................................................................................................................4–1
Before you start ............................................................................................................................................................4–1
Master Filter....................................................................................................................................................................4–2
Full Exception Domain List...........................................................................................................................................4–3
Add............................................................................................................................................................................4–3
Delete........................................................................................................................................................................4–4
Full Exception URL List ................................................................................................................................................4–4
Add............................................................................................................................................................................4–4
Delete........................................................................................................................................................................4–4
Partial Exception Domain List.......................................................................................................................................4–5
Add............................................................................................................................................................................4–5
Delete........................................................................................................................................................................4–5
Partial Exception URL Filter List...................................................................................................................................4–5
Add............................................................................................................................................................................4–5
Delete........................................................................................................................................................................4–5
Banned Domain List .....................................................................................................................................................4–6
Delete........................................................................................................................................................................4–6
Banned URL List...........................................................................................................................................................4–6
Add............................................................................................................................................................................4–6
Delete........................................................................................................................................................................4–6
Banned CSphrase Filter Groups ..................................................................................................................................4–7
Activating Filters........................................................................................................................................................4–7
Deactivating Filters....................................................................................................................................................4–8
Weighted CSphrase Filter Groups................................................................................................................................4–9
Blacklist Domain Filter Groups ...................................................................................................................................4–10
Blacklist URL Filter Groups ........................................................................................................................................4–10
Filter Logging Options ................................................................................................................................................4–11
Enable Full Logging.................................................................................................................................................4–11
Enable Exception Logging.......................................................................................................................................4–11
Length of URL Logged in Access Log.....................................................................................................................4–12
Inactivity Timeout.....................................................................................................................................................4–12
Change Filter Names..................................................................................................................................................4–13
Clear Filter..................................................................................................................................................................4–14
TABLE OF CONTENTS
vii
Search ........................................................................................................................................................................4–15
Exact Match.............................................................................................................................................................4–15
Begins With .............................................................................................................................................................4–17
Any match................................................................................................................................................................4–18
Restart ComSifter Filter..............................................................................................................................................4–19
Display Summary........................................................................................................................................................4–20
Individual Filters ..........................................................................................................................................................4–21
Regular Expression (RegEx)......................................................................................................................................4–22
Explanation of RegEx Modifiers..............................................................................................................................4–22
Examples of RegEx Modifiers.................................................................................................................................4–24
Hours of Operation .....................................................................................................................................................4–25
Normal Operation....................................................................................................................................................4–25
Permanently Off.......................................................................................................................................................4–25
Permanently On.......................................................................................................................................................4–26
Warn-and-Go..............................................................................................................................................................4–27
Enable .....................................................................................................................................................................4–27
Disable.....................................................................................................................................................................4–27
Change Sensitivity......................................................................................................................................................4–28
Sensitivity Level Guidelines.....................................................................................................................................4–28
Copy Filter ..................................................................................................................................................................4–29
Whitelist......................................................................................................................................................................4–30
Setup a whitelist filter: .............................................................................................................................................4–30
Add specific site exception to be whitelisted:..........................................................................................................4–30
Blocking External IP Addresses .................................................................................................................................4–30
Words/Phrases................................................................................................................................................5–1
Overview.........................................................................................................................................................................5–1
Configuring Words/Phrases..........................................................................................................................................5–3
Restart ComSifter Filter................................................................................................................................................5–3
Editing Banned Words/Phrases....................................................................................................................................5–4
Add............................................................................................................................................................................5–4
Delete........................................................................................................................................................................5–4
Editing Weighted Words/Phrases.................................................................................................................................5–5
Add............................................................................................................................................................................5–5
Delete........................................................................................................................................................................5–5
Search ..........................................................................................................................................................................5–6
Users................................................................................................................................................................6–1
Overview.........................................................................................................................................................................6–1
Block User or Computer ...............................................................................................................................................6–2
Block User.................................................................................................................................................................6–2
Enable Block..........................................................................................................................................................6–2
TABLE OF CONTENTS
viii
Disable Block .........................................................................................................................................................6–3
Block Computer.........................................................................................................................................................6–4
Enable Block..........................................................................................................................................................6–4
Disable Block .........................................................................................................................................................6–4
Bypass User or Computer ............................................................................................................................................6–6
Bypass User..............................................................................................................................................................6–6
Enable Bypass.......................................................................................................................................................6–6
Remove Bypass.....................................................................................................................................................6–6
Bypass Computer......................................................................................................................................................6–8
Enable Bypass.......................................................................................................................................................6–8
Remove Bypass.....................................................................................................................................................6–8
User List........................................................................................................................................................................6–10
Display user list by filter...........................................................................................................................................6–11
Display user list alphabetically ................................................................................................................................6–11
User Management Utilities..........................................................................................................................................6–12
Understanding and Determining Transparent and Proxy Modes...............................................................................6–15
Background information ..........................................................................................................................................6–15
Transparent Mode...................................................................................................................................................6–15
Proxy Mode .............................................................................................................................................................6–15
Authenticating Proxy Mode .....................................................................................................................................6–16
Which is the right solution for our network?.........................................................................................................6–16
Proxy Configuration (Group Policy rule)..................................................................................................................6–17
Disabling Local Client Computer Access to Browser Proxy Settings ..................................................................6–18
Authentication Method (Step 1)..................................................................................................................................6–20
Authentication Methods (Pros and Cons)...................................................................................................................6–22
Authentication Methods Explained.............................................................................................................................6–23
BASIC ONLY...........................................................................................................................................................6–23
NTLM with FALLBACK TO BASIC..........................................................................................................................6–24
IDENTD ONLY ........................................................................................................................................................6–25
Download/Install IDENTD ....................................................................................................................................6–26
Port 113 Exception...............................................................................................................................................6–27
Windows Firewall (local rule for XP) ....................................................................................................................6–27
Windows Firewall (Group Policy rule)..................................................................................................................6–31
Install IDENTD .....................................................................................................................................................6–33
IDENTD location ..................................................................................................................................................6–34
Comsift Service Local Install................................................................................................................................6–36
Comsift Service Domain Automated Install (preferred) .......................................................................................6–37
IP ONLY ..................................................................................................................................................................6–39
NO AUTHENTICATION ..........................................................................................................................................6–40
Join ComSifter to AD Domain (Step 2).......................................................................................................................6–41
TABLE OF CONTENTS
ix
Join ComSifter to the AD Domain........................................................................................................................6–41
Full Name of the AD Domain ...............................................................................................................................6–41
Workgroup Name.................................................................................................................................................6–42
Password Server..................................................................................................................................................6–42
Enter Username Authorized to Join the Domain..................................................................................................6–42
Enter Password....................................................................................................................................................6–42
Administer/Retrieve Usernames from Active Directory (Step 3a) ..............................................................................6–43
Preparing Active Directory for Synchronization.......................................................................................................6–43
Administer/Retrieve Usernames from Active Directory...........................................................................................6–46
Populate the user list by a LDAP query to the AD Domain Controller Users and Computers.............................6–46
Host/Domain Name..............................................................................................................................................6–47
Distinguished Name.............................................................................................................................................6–47
AD User Name.....................................................................................................................................................6–47
AD User Password...............................................................................................................................................6–47
Administer/Retrieve Usernames from ComSifter Username Database (Step 3b).....................................................6–48
Adding a new User...............................................................................................................................................6–48
Modifying a User..................................................................................................................................................6–50
Deleting a User ....................................................................................................................................................6–51
Administer/Retrieve User IP’s from ComSifter IP Database (Step 3c).......................................................................6–52
Adding a new IP...................................................................................................................................................6–52
Modifying an IP ....................................................................................................................................................6–54
Deleting an IP.......................................................................................................................................................6–55
Administer/Retrieve Usernames by merging Usernames from an external file (Step 3d)..........................................6–56
Enable/Disable Automatic Proxy Configuration (Step 4a)..........................................................................................6–57
Enable/Disable Automatic Proxy Configuration.......................................................................................................6–57
Overwrite pac/WPAD File........................................................................................................................................6–57
Edit Proxy File proxy.pac/wpad.dat (Step 4b)............................................................................................................6–58
Client Program/Application Bypass (Step 4c) ............................................................................................................6–59
Adding a new Domain/URL..................................................................................................................................6–60
Deleting a Domain/URL .......................................................................................................................................6–60
Merging with Comsift-Maintained Bypass List .....................................................................................................6–62
Turning Off Merge with Comsift-Maintained Bypass List.....................................................................................6–62
Merging with Exception Domain List....................................................................................................................6–64
Turning off Merge with Exception Domain List.....................................................................................................6–64
Client Program/Application Debug Mode (Step 4d) ...................................................................................................6–66
Enable Debug Mode................................................................................................................................................6–66
Raw Data for DENIEDs...........................................................................................................................................6–67
Delete All Usernames from ComSifter........................................................................................................................6–68
Display Summary........................................................................................................................................................6–69
ComSifter Operation.......................................................................................................................................7–1
TABLE OF CONTENTS
x
Network Flow..................................................................................................................................................................7–2
How ComSifter Filters ...................................................................................................................................................7–2
Order of Precedence ....................................................................................................................................................7–2
Categories.................................................................................................................................................................7–3
Blacklist Update.........................................................................................................................................................7–3
CSphrase Filter Technology.........................................................................................................................................7–3
Contact Information............................................................................................................................................1
Location............................................................................................................................................................................1
Phone ...............................................................................................................................................................................1
Sales.................................................................................................................................................................................1
Technical Support.............................................................................................................................................................1
Specifications .....................................................................................................................................................2
Configuration ....................................................................................................................................................................2
Network.............................................................................................................................................................................2
Number of Computers ......................................................................................................................................................2
Throughput .......................................................................................................................................................................2
Typical Access Time.........................................................................................................................................................2
Caching Proxy ..................................................................................................................................................................2
Blacklist Update and Bypass List Update.........................................................................................................................2
Mechanical & Environmental............................................................................................................................................3
Filter Defaults......................................................................................................................................................4
License & Warranty............................................................................................................................................6
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 1–1
Chapter 1
Introduction and Getting Started
ComSifter™ stops the pornography, on-line gambling, and the hate sites at the Internet gateway—before the
offensive material reaches web users. You do not have to worry about web users surfing the Internet. With
ComSifter, if they accidentally misspell a word or use a search word that takes them to the “dark side,” they will
see a friendly message telling them the site has inappropriate content.
Features
ComSifter offers the following features:
Two physically separated, but logically connected, ComSifters offer Non-Stop operation in the event of either
unit failing or either Internet connection failing.
Automatic IP-based load sharing splits Internet load across each ComSifter.
Highly integrated configuration and logging engine allows control over both ComSifters from either unit.
High performance destination-based firewall and content filter.
Stops unauthorized programs from accessing the Internet.
Stops access to pornography, hate, and gambling sites.
Blocks downloading of harmful and illegal files, including MP3 music files.
Filters networks with hundreds of computers.
Intelligent filtering with CSphrase™ Filtering Technology is able to filter based on good words and bad words
found on a web page.
Eight individually configurable filters. Users may be set to the filter that best fits their filtering needs.
Active Directory integration.
Gigabit Ethernet speeds.
High-performance SSD hard drive.
Advanced authentication methods, including Basic, NTLM, IdentD, and IP.
Automatic Browser Configuration.
Bridge Mode.
Support for YouTube for Schools.
Advanced re-write capabilities.
800,000+ sites Blacklist updated daily or weekly.
Built-in DHCP server, DNS forwarding, and caching proxy.
Easy to install—no required maintenance.
Unlimited licensing is standard.
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 1–2
How ComSifter Works
Figure 1-1: ComSifter Architecture
ComSifter Architecture
Firewall
(loc)
Firewall
(net)
DHCP/DNS
Services
Proxy
Service
Content
Filtering
Comsift
Engine
Connection
Manager
Outbound
Rules
Look at the
outbound packs
to see if any
rules are
matched. If not,
reject the
packets.
DHCP Server
If enabled, gives
out IP addresses
to client
computers
DNS Forward-
ing
Always enabled.
If a DNS request
is received, it is
forwarded to the
DNS Servers
listed in the
Network
Wizards.
Inbound Rules
Examine
inbound packets
for rules match.
Drop packet if no
match.
Remote
Administration
Keep list of
allowed IP
addresses. If
packet IP
matches, let it in.
Follow My IP
Keep list of
FQDNs. Every
15 minutes,
check if IP of
FQDN has
changed.
Dynamic DNS
Every 15
minutes, monitor
IP of ComSifter.
If it changes,
update new IP
info to Dynamic
DNS site.
DHCP Client
Get WAN IP
from upstream
device
PPPoE Client
Get WAN IP
from upstream
device
Static
Use internal
WAN setting to
communicate
with upstream
device.
Heartbeat
Monitor the
connection by
downloading a
heartbeat file
every five (5)
minutes. If
heartbeat fails,
go into Non-Stop
mode.
Configuration
Allows the
ComSifter to be
configured by
way of a browser
Logging
Logs user
activity, firewall
(packet) activity,
system
messages, and
Top Sites.
User Database
Maintains
usernames and
filter mappings.
Active
Directory Sync
If part of a
domain, maintain
binding with
domain. Update
domain user list
every 15
minutes.
Blacklist
Updates
Daily or weekly
blacklist updates
Software Check
Daily check for
software
updates.
Authorization
The user is
authenticated,
what are they
authorized to do
(filter mapping)?
Bypass/Block
User/Computer
See if the
user/computer is
in a block or a
bypass rule
Time of Day
Is the filter the
user is mapped
to active?
Exception List
Is the requested
site on an
exception list?
Blacklist
Is the requested
site on a
Blacklist?
Words/Phrases
Run the
requested page
through
Words/Phrases
Matched
If any of the
above is
matched, give
the user a
Denied Access
page; otherwise,
give the user the
page.
Identify and
Authenticate
User or
Computer
(Authentication
Method)
We need to
identify and
authenticate who
is asking to
come through
ComSifter.
NTLM, IdentD,
Basic, and IP
methods are
supported.
Not Authenti-
cated
If the user is not
authenticated, is
the URL on the
Proxy Bypass
List?
Fetching
Once authenti-
cated, the
ComSifter gets
the requested
page from the
Internet and
presents it to the
Content Filter.
Caching
Check the
headers for
caching status. If
allowed, save to
local storage for
subsequent use.
Client Computers Internet
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 1–3
Overview
ComSifter is a standalone appliance that connects your internal LAN to the Internet while seamlessly offering
firewall and content filtering.
Internet Gateway
ComSifter is the gateway device from a private LAN to the public Internet. It is able to operate as a standard
router or in a Network Address Translation (NAT) mode. In the NAT mode, ComSifter converts internal IP
addresses to a public IP, effectively isolating your private network from the Internet.
Non-Stop Operation
Two ComSifter Non-Stop units, in conjunction with two Internet connections, offer a reliable Internet connection
for organizations that cannot afford any down time. A state-of-the-art failover-enabled DHCP server performs
IP/gateway-based load balancing while instructing client computers that there are two gateways to the Internet.
Each ComSifter performs a series of steps every five minutes to determine if a valid Internet connection is
available. If not, the ComSifter will shut down its LAN interface. This shutdown will trigger Dead Gateway
Detection on client computers using this gateway. Client computers will then switch to the other ComSifter.
This same process will occur if either ComSifter is lost due to a hardware failure.
Firewall
An industrial strength, rules-based stealth firewall is included in ComSifter. The firewall allows complete control
of all ports from the Internet to the LAN and from the LAN to the Internet. The resolution of the firewall is such
that a single port on a single computer on the LAN can be allowed to a single port on a single IP on the
Internet. The firewall can block internal port hopping programs, has log rate limiting, and does not over react to
Denial of Service attacks. Full logging of every transaction is available.
Filtering System
ComSifter CS-8D Pro incorporates eight individual filters. Each filter may be individually configured for the user
computers that access the filter. Additionally, a global filter allows configuration system wide.
When the user computer accesses a filter, two types of filtering are performed:
First, ComSifter compares the requested site with its blacklist to determine if the address has already
been deemed inappropriate. If the site is blacklisted, the user will receive a Denied Access Page, and
will not be able to view the site.
Second, if the site is not blacklisted, ComSifter will scan every word on the Internet page, using its
CSphrase Filtering Technology, looking for words that indicate inappropriate content. The context of
these words is analyzed to determine if the page should be blocked. This greatly reduces the number of
false positives while blocking those pages that are offensive. This feature accounts for ComSifter’s
remarkable accuracy.
If the content passes through both types of filtering, ComSifter allows the page to be loaded on the user’s
computer. If either of the filters disallow, a “Denied Access Denied” page is sent to the user’s computer. All this
is done in a fraction of a second, with no delay seen by the user.
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 1–4
Using This Guide
This User Guide is designed for the technical person that will be installing, configuring and operating the
ComSifter network content filtering device.
The following list summarizes the chapters and appendixes that follow this chapter.
Chapter 2, Installing ComSifter — describes how to install and physically connect ComSifter to your network.
Chapter 3, Configuring ComSifter — describes how to configure ComSifter. This includes setting up
administrators, configuring network and firewall settings, and describing maintenance items.
Chapter 4, Filter Setup — describes how to configure the Master Filter and each individual filter.
Chapter 5, Words/Phrases — describes the configuration of ComSifter’s CSphrase filter.
Chapter 6, Users — describes how to Add/Modify/Delete users to the database.
Chapter 7, ComSifter Operation — describes the operation of ComSifter.
Appendix A, Contact Information —provides contact information including telephone numbers, address, email and
hours of operation.
Appendix B, Specifications — provides technical information about the ComSifter.
Appendix C, Filter Defaults — provides default information for the eight filters.
Appendix D, License and Warranty — provides information about ComSifter’s licensing and warranty.
Navigating Through This User Guide
This User’s Guide contains all the information you need to install, use, and troubleshoot ComSifter. To assist
you in navigating through this document, we have added blue-colored hot links to the Table of Contents, index,
chapters, and appendixes in this User’s Guide. Clicking one of these hot links automatically moves you to that
location in this User’s Guide. For example, if you click one of the blue-colored chapter or appendix titles in the
previous section, you automatically move to the first page in that chapter or appendix.
Conventions in This User’s Guide
This User’s Guide uses the following conventions:
NOTES are information requiring extra attention.
TIPS are helpful procedures or shortcuts for simplifying a task.
IMPORTANT is information that, if not followed, may affect the proper operation of the product.
WARNING is information that if not followed or understood, may affect the operation of the product, the
operating system, or the system configuration.
Bold is used to denote an item that is to be clicked or selected.
Note: If you wish to print a hard copy of this guide, it has been formatted to fit on
standard letter-sized 8.5x11” paper.
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 2–1
Chapter 2
Installing ComSifter
This section of the guide is designed to be used as a Quick Start Guide. The guide will assist you in configuring
your ComSifter and will give time estimates for each procedure.
In this chapter, we will discuss the physical installation of ComSifter and how to connect a browser to
ComSifter in preparation for configuration. ComSifter installs between your connection to the Internet and
Internal LAN as shown in the diagramsbelow.
Figure 2-1: ComSifter(s) in the Network
Internet
CONNECTION TO
INTERNET SERVICE
PROVIDER(S)
Client/User
INTERNAL IP
192.168.1.20
GATEWAYS
192.168.1.1
192.168.1.2
INTERNAL IP
192.168.1.2
ComSifter
Secondary
Optional
ComSifter
Primary
or Single
Cable/DSL/T1
Modem
Cable/DSL/T1
Modem
EXTERNAL IP
INTERNAL IP
192.168.1.1
EXTERNAL IP
Client/User
INTERNAL IP
192.168.1.21
GATEWAYS
192.168.1.2
192.168.1.1
Client/User
INTERNAL IP
192.168.1.23
GATEWAYS
192.168.1.1
192.168.1.2
Wireless Access
Point
INTERNAL IP
192.168.1.24
GATEWAYS
192.168.1.2
192.168.1.1
10/100/1000
BASE-T Switch
Server/Domain
Controller
INTERNAL IP
192.168.1.25
GATEWAYS
192.168.1.1
192.168.1.2
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 2–2
Figure 2-2: ComSifter in Bridge mode
Internet
CONNECTION TO
INTERNET SERVICE
PROVIDER
Client/User
INTERNAL IP
192.168.100.20
GATEWAY
192.168.100.1
ComSifter
in Bridge Mode
Cable/DSL/T1
Modem
Router
INTERNAL IP
192.168.100.9
w
ith the
C
om
S
ifte
r
INTERNAL IP
192.168.100.1
Client/User
INTERNAL IP
192.168.100.21
GATEWAY
192.168.100.1
Client/User
INTERNAL IP
192.168.100.23
GATEWAY
192.168.100.1
Wireless Access
Point
INTERNAL IP
192.168.100.24
GATEWAY
192.168.100.1
10/100/1000
BASE-T Switch
Server/Domain
Controller
INTERNAL IP
192.168.100.25
GATEWAY
192.168.100.1
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 2–3
Installation
Security Considerations
ComSifter should be placed in a location that meets the security considerations of your organization. A
possible consideration for a pair of Non-Stop ComSifters is to place them in two different physical locations.
This will reduce the risk of a local environmental condition affecting both ComSifters.
Location/Placement
ComSifter should be installed in a clean, dry location located near your DSL, cable, or T1 modem connection.
The location must be within the operating temperature range of ComSifter (50–95°F or 10–35°C).
Note: If the unit becomes overheated, the unit will sound an audible tone—a constant
beep—until the condition is cleared.
The preferred placement of a ComSifter unit is in the horizontal position. If vertical placement is required, then
attach the included rubber feet to the left side surface of the ComSifter (the side closest to the power button).
One (1) inch clearance is required on the sides and top, regardless of the placement orientation.
AC Power
Connect the supplied AC power cord to the ComSifter power adapter and a properly grounded 115VAC
outlet. Connect the power supply output cable to the ComSifter. Although not required, best practices would
suggest that ComSifter be placed on a UPS system. This will protect ComSifter from most external power
fluctuations and allow continued operation in the event of a momentary power outage.
Network Connections
ComSifter requires two network connections. Connect the Ethernet connector, marked “WAN,” to your DSL,
cable, or T1 modem (or, if in Bridge Mode, connect it to your router). Connect the Ethernet connector, marked
“LAN,” to your internal LAN switch. Either Ethernet connector may use 10BASE-T, 100BASE-T, or 1000BASE-
T.
Power On and Indicator Lights
After all connections are made, ComSifter may be powered on by pressing the power switch on the front of the
unit. The blue indicator light indicates that ComSifter is powered on and functioning normally.
Note: After powering on, ComSifter will take approximately one (1) minute before it is
ready for operation.
To power off ComSifter, press the power button. All indicator lights will extinguish.
INSTALLING COMSIFTER
User Guide | ComSifter CS-8D Pro 2–4
Audible Tones
Audible Tone Frequency Issue Resolution
Slow Beep One (1) beep every
three (3) seconds for
30 seconds—then no
beeps for 4½
minutes. Repeats
every five (5)
minutes.
Duplicate IP on the
WAN side of the
ComSifter
Internet Service Provide (ISP) has
duplicated the IP assigned to the account.
Condition may clear after a few minutes. If
it does not clear, it will be necessary to
contact the ISP.
Fast Beep One (1) beep every
second for 30
seconds—then no
beeps for 4½
minutes. Repeats
every five (5)
minutes.
Duplicate IP on the
LAN side of the
ComSifter
More than one device is serving DHCP
information, or another device on the
network has been manually assigned the
same IP address as the ComSifter.
Constant Beep Continuous Overheating condition The ComSifter is not receiving proper air
circulation or the internal fan has stopped
working.
Short Beep Twice/short During the boot
sequence, or if a
network cable has
been removed and
reinserted
None
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