Allworx Allworx 10x Quick reference guide

Allworx 10x
Networking White Paper

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10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
© 2006 InSciTek Microsystems, Inc. All rights reserved. Allworx is a registered trademark of InSciTek Microsystems. All other names may be
trademarks or registered trademarks of their respective owners.
Revised: February 8, 2007
Page i
Table of Contents
1Introduction...................................................................................................................................................1
2The WAN Interface and your Internet Service Provider (ISP).......................................................................2
3IP Addresses, Netmasks, Gateways.............................................................................................................3
4Allworx Networking Security - Firewalls and NAT.........................................................................................4
4.1 Firewall..................................................................................................................................................4
4.2 Network Address Translation (NAT) .....................................................................................................4
4.3 Mode Summary.....................................................................................................................................5
5Dynamic Host Configuration Protocol (DHCP) .............................................................................................6
6Domain Name Server (DNS) and Domain Names........................................................................................8
6.1 Settings Summary.................................................................................................................................8
7Mail Configuration and Unified Messaging .................................................................................................10
8Allworx as the Primary Mailbox...................................................................................................................12
8.1 Inbound via SMTP ..............................................................................................................................12
8.2 Inbound via POP3...............................................................................................................................12
8.3 Mailbox Access...................................................................................................................................13
9Allworx as a Secondary Mailbox.................................................................................................................14
9.1 Pull Model: Unified at the Client.........................................................................................................14
9.2 Push Model: Replicated by Allworx.....................................................................................................14
10 Advanced Topic: Using Allworx to host your DNS Domain.....................................................................15
11 Advanced Topic: IP Telephony and Quality of Service Issues ...............................................................21
11.1 WAN VoIP...........................................................................................................................................21
11.2 LAN VoIP ............................................................................................................................................21

10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
© 2006 InSciTek Microsystems, Inc. All rights reserved. Allworx is a registered trademark of InSciTek Microsystems. All other names may be
trademarks or registered trademarks of their respective owners.
Revised: February 8, 2007
Page 1
1 Introduction
The Allworx®10x Server is designed to meet the communications and networking needs of the typical small
business, while also simplifying the setup and maintenance of the IT infrastructure for the business owner. The
problem is that the typical small business is not always so typical and the landscape of protocols, providers,
and terminology can be somewhat overwhelming.
This paper is intended as an explanation of key networking fundamentals for the small business owner who is
considering an Allworx 10x. An understanding of the decisions and configuration options should improve a
non-technical owner’s control and effectiveness as s/he establishes a workable infrastructure that meets the
needs of the business, today and tomorrow.

10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
© 2006 InSciTek Microsystems, Inc. All rights reserved. Allworx is a registered trademark of InSciTek Microsystems. All other names may be
trademarks or registered trademarks of their respective owners.
Revised: February 8, 2007
Page 2
2 The WAN Interface and your Internet Service Provider (ISP)
Allworx provides simple and secure access to the Internet for users on your company’s Local Area Network
(LAN). This capability is sometimes referred to as “Internet Connection Sharing,” since there is a single Internet
connection shared by all LAN users, rather than individual connections. In this role Allworx acts as your local
networking router. While you won’t need to purchase any other equipment to get connected to the Internet,
unfortunately Allworx [like other network systems] can’t get to the Internet by itself; you will also need the
services of an Internet Service Provider (ISP) to actually physically connect to the Internet.
Connecting to the Internet or any other external network is the role of the Wide Area Network (WAN) interface
of your Allworx unit. Generally, when you set up Allworx to share your connection with all the PC’s on your
LAN, the Allworx WAN interface is used to hook to your ISP provided modem or router. Allworx is designed to
look like a single ordinary PC when connecting your LAN to the Internet and should work with any ISP service
provider equipment that allows you to hook to the Internet using a standard 10/100 Ethernet cable between
Allworx and the ISP provided equipment. This includes just about any Cable Modem, DSL modem or T1 based
services that use standard TCP/IP networking between you and the ISP.
When configuring your Allworx system for Internet access, you will need to know the following from your ISP
provider:
• Static IP Address or Dynamic (DHCP Client) IP Addressing
• DNS Server IP Address(es)
• IP Netmask and Gateway Settings
When your system is being installed and set up, your system administrator or consulting installer will enter
these addresses and settings in the system ‘Network Settings’ segment of the Allworx Administrator web page.
To give you some idea of the significance and background to these settings, the following sections are offered
as a brief tutorial.

10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
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Revised: February 8, 2007
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3 IPAddresses, Netmasks, Gateways
All computers that connect to the Internet using the TCP/IP protocol have to be configured such that each
computer on the Internet knows how to locate every other computer on the Internet. This is done with a unique
set of network settings which consists minimally of an Internet Protocol (IP) Address, a Netmask, and a
Gateway Address. The IP address gives the PC or server [host in networking terminology] a unique identity on
the Internet so that when any computer wants to send data to it, it knows where to find it. It is sort of like a
Social Security number for computers. That address must be unique for every computer on the Internet so that
data sent on the network gets to the right place.
Most people somewhat intuitively understand IP addresses so we won’t spend lots of time on that. Suffice it to
say that the IP address of each and every host must be unique on the Internet so that traffic knows where it is
going. On the other hand, the terms netmask and gateway go beyond many people’s knowledge of networking.
Fortunately, the concepts are simple and the early engineers of the Internet did a great job of making the
roadmap of the Internet easy to follow. In short, netmask and gateway give each host a way to find any other
host on the Internet and form the basis for routing decisions on the Internet
When a host wants to send a packet of data to another computer, it needs to know how to find that computer.
Fortunately, the decision is simple and can be answered with one simple question: “Is the host I want to talk to
local or remote?” The Netmask is used to figure out the answer to this question. The host uses its own IP
address, the destination host IP address and the netmask to determine if the desired location is local or
remote. If the answer is local, then the packet is sent directly to the destination via the LAN’s hub or switch
using the physical MAC address of that computer. If the answer is remote, then the host is needs to activate
the services of a router to forward the packet along to its destination. How does the host find a router to do
this? The Gateway is the IP address of the necessary router for your LAN.
How do I know what the right IP, Netmask, and Gateway Settings are for my Allworx unit? – Good Question! –
Since Allworx typically acts as both a router and a host, there are actually two sets of settings (WAN and LAN)
for the Allworx unit with the gateway address always being the same for both sets of settings. For the WAN
interface, they will be provided by your ISP or set automatically via a protocol called DHCP (discussed more
later). For the LAN, generally the factory defaults will be sufficient.
Note: All controls for these configuration options are on the Network Settings page of the Allworx admin tools.

10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
© 2006 InSciTek Microsystems, Inc. All rights reserved. Allworx is a registered trademark of InSciTek Microsystems. All other names may be
trademarks or registered trademarks of their respective owners.
Revised: February 8, 2007
Page 4
4 Allworx Networking Security - Firewalls and NAT
As a complete solution for your IT infrastructure, Allworx includes enterprise class Firewall security and TCP/IP
routing functions to support moving (or blocking!) traffic between the private LAN and Public WAN interfaces of
your Allworx unit. The Allworx Firewall, routing modes, and Network Address Translation (NAT) all go hand in
hand to provide this capability. We’ve built in a wide range of options designed to support a variety of typical
small business networking setups.
Note: All of these options are configured on the Security Settings” page of the Allworx Networking
administrative area.
Because of the advanced capabilities available, this particular topic can get very involved. The Allworx unit is
intended to be as flexible as possible in this area to meet various demanding applications typical of more
complex environments, without getting too complicated for the average user. To start the conversation, let’s get
some definitions out of the way:
4.1 Firewall
Most people have heard of firewalls, but what do they really do? In brief, they protect your private LAN network
from external access by unwanted traffic. At a lower level, a firewall is a special type of network router. Normal
routers follow all the normal Internet TCP/IP network routing rules without regard to security concerns, while a
firewall introduces policy on the routing decisions above and beyond the original rules of Internet traffic.
Generally, these policy decisions are based on the IP addresses involved in the transaction and the physical
interfaces the packets are coming from or going to.
In the context of Allworx specifically, the physical interfaces are the LAN and WAN interfaces of your unit.
When the Allworx firewall is enabled, by default, all internal LAN traffic is allowed Internet access to the
outside, but nobody on the Internet is allowed access to your LAN. In fact, the Allworx Firewall is the most
powerful form of Firewall – The Stateful Packet Inspection (SPI) filtering Firewall, for maximum system safety
at all times.
4.2 Network Address Translation (NAT)
As discussed in a previous section, we stated every host on the Internet must have a unique IP address. This
is not entirely true. A more correct statement would be to say that every host on the Internet must appear to
have a unique IP address from the point of view of the Internet. This is a subtle but important distinction. NAT
allows multiple hosts on a LAN to share a single public IP address. Using NAT solves several potential
problems:
• IP Addresses are running out. There are many more computers that have Internet access than there
are IP addresses to go around…amazingly enough!! While there are theoretically 4-billion IP addresses
to go around, certain technical factors that simplify routing decisions waste lots of potential addresses.
This makes a public IP address a valuable commodity that costs money.
• Most ISP’s only provide you one IP address as part of your service (perhaps up to five for “free”) and
additional ones are typically rented on a monthly basis. NAT allows you to have more hosts on your
LAN than public IP addresses. With Allworx as your NAT/Firewall, you only need one public IP to give
all your computers on the LAN access to the Internet!
• Public IP Addresses have to be maintained as unique and routing tables must be updated at your ISP
when things change or move around. NAT enables the use of private IP address ranges that you can

10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
© 2006 InSciTek Microsystems, Inc. All rights reserved. Allworx is a registered trademark of InSciTek Microsystems. All other names may be
trademarks or registered trademarks of their respective owners.
Revised: February 8, 2007
Page 5
manage and change on your own without permission or support from your ISP. In the case of Allworx
NAT capabilities, it will manage the private addresses for you automatically!
• Public IP addresses provide an address for hackers to attack. NAT hides the true IP address of hosts
on your LAN under a single public address, making it harder for hackers to understand things about
your network. NAT alone does not replace a firewall. However, NAT combined with a Stateful Packet
Inspection Firewall provides added security. Allworx provides this additional level of security: when the
Allworx Stateful Packet Inspection Firewall is enabled, NAT is automatically enabled as well.
4.3 Mode Summary
With the definitions out of the way, we will explore the various security modes of your Allworx unit and explain
what each mode is:
• LAN only Mode – This mode is used when the WAN interface of Allworx is not needed. In this mode
Allworx works like an ordinary LAN host and typically provides no routing, NAT, or firewall functions
since all traffic is bound to the LAN interface only. If Allworx is configured as a DHCP server (see
DHCP later), it will assign a netmask and gateway to hosts based on its own LAN interface netmask
and gateway settings.
• Router Mode – This mode is used when Allworx is used as an ordinary two port router with the Allworx
providing the routing functionality between the LAN and WAN interface. This mode is typically used
when your LAN addresses need to be public or when the WAN interface is connected to another
internal sub-network. The firewall and NAT is always disabled in this mode. If Allworx is configured as a
DHCP server, Allworx will assign itself as the LAN gateway to the WAN.
• Firewall/NAT Mode – This mode (by default) makes the LAN completely secure from the WAN interface
and only outbound connections are allowed from LAN to WAN. In addition, all traffic from LAN to WAN
and back is translated through the NAT mechanisms to allow sharing of the Allworx WAN IP address
with all hosts on the LAN. Connections from WAN to LAN are always refused, by default configuration.
However, when desired, specified LAN devices can be made visible on the WAN. Note: Allworx’s own
public services are still directly available on the WAN, but the LAN side services (intranet, admin, etc).
are fully secured.
• Firewall/NAT/DMZ Mode – This is identical to the previous mode, except the firewall mechanisms are
also applied to Allworx’s own public WAN interface. As a result, your unit is more resistant to various
forms of known Internet attacks, such as denial-of-service type attacks. Your LAN is always protected
when the firewall is enabled, but DMZ mode increases protection for the Allworx external WAN
interface. With DMZ enabled, you can selectively control which WAN protocol ports are even visible on
the Internet. This is sometimes referred to as a “stealth mode.”

10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
© 2006 InSciTek Microsystems, Inc. All rights reserved. Allworx is a registered trademark of InSciTek Microsystems. All other names may be
trademarks or registered trademarks of their respective owners.
Revised: February 8, 2007
Page 6
5 Dynamic Host Configuration Protocol (DHCP)
There is usually much confusion over DHCP. This is particularly ironic because the DHCP protocol is intended
to make the life of the users and administrators easier. While the protocol is quite involved, what it does is
actually really simple to understand. The confusion arises because of the notion of DHCP client and server
modes. Let’s clear this all up now!
Recall that all hosts on the Internet have to have a unique IP address, a netmask and a gateway setting to
participate on the Internet. Historically, this was all set manually on each computer when the operating system
is installed and the host is placed on a network. This is referred to as “static IP addressing”. This creates two
potential difficulties, one for the end user and one for the administrator:
• For the administrator this means every computer has to be configured and maintained manually. A
network or ISP change may affect every computer on the network and each would have to be updated
by hand, separately!
• For the end user they can’t relocate a computer to other networks without manually re-configuring each
time. For a desktop PC this is potentially not a concern, but for a laptop computer you move between
offices or work and home…it’s a real inconvenience!
The DHCP protocol addresses these problems through two pieces of software.
1) A DHCP server program maintained by the network administrator; and
2) A DHCP client program that is usually part of the operating system for any network driver/adapter.
Using DHCP and the laptop computer example you simply plug into any network drop and once Ethernet link is
acquired the DHCP client automatically queries for the local DHCP server on the network who then answers
the client’s query and automatically provides the correct settings for that particular LAN. IP addresses are still
unique to each computer, but they are maintained in a pool and re-circulated, as needed, using leases.
There is only one real drawback to DHCP – Your IP address can change over time! This is especially true
when you turn off your computer for the lease duration or if you have a laptop and it moves around between
networks often. While this is not generally of concern for a regular PC or laptop this is a problem for servers,
especially public ones! You want to always have people find your servers at a known “address”. This facilitates
the need to still maintain tables of “statically assigned” IP addresses.
Relative to Allworx, because of its extensive breadth of capabilities it can provide the role of both DHCP server
and DHCP client, simultaneously, depending on the particular application. The DHCP server mode applies to
Allworx providing the DHCP service to computer hosts on your private LAN. While the default settings of the
Allworx DHCP server are generally sufficient, there is quite a bit of control over its behavior, including disabling
the server. These settings can be manipulated through the “Servers – DHCP” page of the administrative tools.
Note there should only be one DHCP server enabled per LAN network.
To make the DHCP server as seamless as possible, most settings the DHCP server provides to LAN clients
are determined automatically for you! This is one of the ways Allworx simplifies configuration and setup of your
network. However, for the more curious or technically inclined, we’ll describe how Allworx decides what values
to assign:
• IP Address – The IP Address is always a LAN address from the available pool. Allworx defaults to
assigning addresses from the dynamic range of “1” through “100” on the LAN subnet, skipping its own
address if it overlaps. This range can be adjusted on the DHCP server settings page if desired. Allworx
will assign addresses for up to 254 hosts on the LAN.

10x Networking White Paper
300 Main Street • East Rochester, NY 14445 • Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
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trademarks or registered trademarks of their respective owners.
Revised: February 8, 2007
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• Netmask – This is always directly inherited from the Allworx LAN netmask setting and assigned
accordingly.
• Gateway IP – The gateway setting is delivered as Allworx’s own IP address when Allworx is configured
as a network firewall or as a router. However when Allworx is configured in “LAN only mode” this setting
is directly controlled by Allworx’s own gateway address, entered on the Network Settings page.
• DNS Server IP – The DNS server IP address given out is delivered as Allworx’s own IP address when
Allworx is configured as a network firewall or as a router. However, when Allworx is configured in “LAN
only mode” this setting is directly controlled by Allworx’s own primary DNS server IP address, entered
on the DNS Server settings page.
• Default Domain – The domain is always driven from the domain setting entered on Allworx Network
Settings page.
• Time Server – If the host on the LAN requests time services, Allworx will always provide its own IP
address as the LAN time server.
The Allworx DHCP client side functionality applies to Allworx’s WAN port only. With the Allworx DHCP client
service enabled, Allworx can automatically configure its own WAN interface through a separate DHCP server
available on the WAN interface. This DHCP server would generally be maintained by your ISP and is very
common with lower cost Internet services where a static IP address is not provided. Allworx will automatically
configure its own WAN IP Address and Netmask from the external DHCP server.
Note: For security reasons, the Allworx Domain Name and DNS server IP address settings must always be
entered manually by the administrator.