Ntron 708 Series Owner's manual

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708, 709FX, 710FX2, 711FX3, 712FX4, 714FX6,
716, 7010TX, 7012FX2, 7018, & 7506GX2 Series
Managed Industrial
Ethernet Switch
DHCP Technical Instructions

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Contents
Contents .................................................................................................................................................................. 2
Overview................................................................................................................................................................. 3
Configuring DHCP Server and Relay Agent.......................................................................................................... 4
Examples................................................................................................................................................................. 4
N-Tron DHCP Setup Process –Basic Setup Flow ................................................................................................. 5
Getting connected with N-Tron DHCP Server....................................................................................................... 6
DHCP Menu............................................................................................................................................................ 6
Figure: Menu_1................................................................................................................................................... 6
Enabling the DHCP Server ................................................................................................................................. 7
Setting up the DHCP Server Profiles.................................................................................................................. 7
Figure: Profile_1.............................................................................................................................................. 7
Setting up the DHCP Server Mappings .............................................................................................................. 8
Figure: Mapping_1.......................................................................................................................................... 8
Setting up a Dynamic Range............................................................................................................................... 8
Topology:......................................................................................................................................................... 8
Setting up a Static Range .................................................................................................................................. 10
Basic configuration using Option 82 Relay Agent........................................................................................ 10
Topology:....................................................................................................................................................... 10
N-Tron Relay Agent Setup Process –Basic Setup Flow.................................................................................. 12
Setup Option 82: Relay Agent Switch........................................................................................................... 13
N-Tron DHCP Server Static Range Setup Process –Basic Setup Flow........................................................... 14
Setup Option 82: DHCP Server Switch......................................................................................................... 15
Setting up a Single IP........................................................................................................................................ 17
Basic configuration using Option 61 or MAC Address ................................................................................ 17
Topology:....................................................................................................................................................... 17
Setting up an N-Tron Switch as a Client Device.................................................................................................. 19
Topology ........................................................................................................................................................... 19
Example............................................................................................................................................................. 19
Relay Agent - Stand Alone................................................................................................................................... 21
Setting up the Relay Agent to obtain a Local IP Address................................................................................. 21
Topology:....................................................................................................................................................... 21
Advanced DHCP Server Topologies .................................................................................................................... 22
Setting up a redundant DHCP Server using 2 N-Rings across N-Link............................................................. 22
Topology 1:.................................................................................................................................................... 22
Firmware/Config –TFTP ..................................................................................................................................... 29
SUPPORT............................................................................................................................................................. 31
N-TRON Limited Warranty.................................................................................................................................. 32

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Overview
The Dynamic Host Configuration Protocol (DHCP) provides configuration parameters to Internet hosts.
DHCP consists of two components: a protocol for delivering host-specific configuration parameters from a
DHCP server to a host and a mechanism for allocation of network addresses to hosts. DHCP is built on a
client-server model, where designated DHCP server hosts allocate network addresses and deliver
configuration parameters to dynamically configured hosts. (DHCP is explained in RFC 2131).
The N-Tron DHCP Switch can be configured to be a DHCP Server, a DHCP Relay Agent, or both.
DHCP Server - manages and allocates IP address from a pool of address, defined by Profiles, to
requesting Clients.
Relay Agent –receives DHCP requests messages and directs them to a specific DHCP server.
Before sending the DHCP request, the Relay Agent appends identifying information into the
message (Circuit ID + Remote ID).
oCircuit ID –contains information that identifies the port location that the DHCP request
comes from. For example (TX1-0001) defines request came from Port 1 –VLAN 1.
oRemote ID –contains information that identifies the Relay Agent device. (For example: the
IP address or MAC address of the Relay Agent.)
It can also Assign a Local IP address when a client is connected to a specific port. Relay Agent is
explained in RFC 3046.
The N-Tron DHCP Server supports several methods of allocating IP address in a managed manner.
Dynamic Range –IP address allocation is Dynamic and is based on the first free IP address in the
defined range. The IP address could be different each time the Client makes a request.
Static Range: Option 82 Relay Agent- IP address allocation is Static and is based on matching
Option 82 information received from a Relay Agent. The same IP address will be given each time to
a specific Client.
Single IP: Option 61 or MAC - IP address allocation is Static and is based on matching Option 61
information received from a Client. The same IP address will be given each time to a specific
Client.

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Configuring DHCP Server and Relay Agent
The following information will be helpful as you configure the N-Tron DHCP Server. A high level flow of
the basic configuration is provided by Figure: Flow_DHCP_1.
In order to use the DHCP server in offering IP addresses, several configuration steps are essential. N-Tron
uses Profiles and Mappings to organize how the IP’s will be offered to Clients. You must have at least one
Profile defined in order to add mappings.
The menu Setup Profiles shows DEFAULT as a Profile. The DEFAULT Profile allows you to define some
changeable parameters that are automatically included within the Profile you define. The changeable
Profile entries can be seen by pressing the, Advanced, button when adding a Profile. You do not have to
make use of this DEFAULT Profile. The DEFAULT Profile information is used by the DHCP Server when
communicating with the DHCP Client. The use of the DEFAULT Profile simplifies the changing of
information of already defined Profiles by automatically inserting data found in the DEFAULT profile into
the Profile used when allocating an IP addresses to a Client.
The Profile Setup has entries to define an Address Pool range. It is important to decide what this range
should be, since your IP address mappings will be a subset of this range. Profiles cannot overlap their
Address Pool ranges with other Profiles.
The Profile Setup Lease Time: designates the amount of time an IP will be honored by a Server that has
made an offer to a Client. The Lease Time insures that the IP address offered by the Server will not be
offered to any other Client device until the Lease expires. The Client will use a renewal process to maintain
the IP for longer periods of time by requesting an extension for the address from the server.
Saving DHCP Settings and Data: The DHCP Profiles, Mappings and Bindings are stored in the N-Tron
switch file system when you click on the screen Update button. These changes are automatically saved for
you. Parameters such as Enabling and Disabling the DHCP Server are part of the switch Settings
configuration and you will be prompted by a message to save your changes.
Examples
Examples are provided for the following settings:
Setting up a Dynamic Range
Setting up a Static Range
Setting up a Single IP
Setting up an N-Tron Switch as a Client Device
Setting up the Relay Agent to obtain a Local IP Address
Setting up a redundant DHCP Server using 2 N-Rings across N-Link

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N-Tron DHCP Setup Process –Basic Setup Flow
DHCP Server
Enable DHCP
Server
DHCP Server
Setup Profiles
DHCP Server
Setup IP Maps
Relay Agent
Relay & Local IP
Setup
N-Tron Client
Switch
Setup DHCP Client
DHCP Server
Create
Dynamic Range
DHCP Server
Create
Static Range
DHCP Server
Create
Single IP
N-Tron
DHCP Setup
Process
Figure: Flow_DHCP_1

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Getting connected with N-Tron DHCP Server
N-Tron Switches provide a Web Interface for all your DHCP configurations.
The two main menus for DHCP configuration are:
DHCP –contains the configuration for both the DHCP Server and Relay Agent.
Administration –clicking on Administration / System / IP Configuration menu, allows you to
configure the DHCP Client to be either Static or DHCP. In order to receive an IP address
from a DHCP Server the switch must be configured for DHCP.
DHCP Menu
Figure: Menu_1

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Enabling the DHCP Server
Click on: DHCP / Server / Setup Profiles. See Figure: Menu_1
Click on: Modify Button. See Figure: Setup_1
Click on Server Enabled Box and select Enabled.
Click on Update Button.
Click on Saved.
Figure: Setup_1
Setting up the DHCP Server Profiles
Click on: DHCP / Server / Setup Profiles. See Figure: Menu_1
Click on: Add Profile button. See Figure: Setup_1
Enter a Network Profile Name: Ex. One
Enter an Address Pool Start: Ex. 192.168.2.1
Enter an Address Pool End: Ex. 192.168.2.254
Click on Update when finished.
Figure: Profile_1

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Setting up the DHCP Server Mappings
Mappings are used to define rules that are used in determining what IP address will be
offered to the client.
N-Tron provides the following Mapping Types:
Figure: Mapping_1
Setting up a Dynamic Range
IP address allocation is Dynamic and is based on the first free IP address in the defined
range. The IP address could be different each time the Client makes a request.
Topology:
DHCP
Client
Example:
In this example connections can be made to any port on the server or on a switch connected to the
server. The IP address given will be the next available address in the range defined.
Setup:
Click on: DHCP / Server / Setup IP Maps. See Figure: Menu_1
Click on: Dynamic Range. See Figure: Mapping_1
Reference Figure: Dynamic_1 below.
Select the Profile you wish to add this mapping too.
Enter Low IP: Ex. 192.168.2.25
Enter High IP: Ex. 192.168.2.35
Click Update when finished.
Figure: Dynamic_1

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Mapping:
The resulting mapping from the setup can be viewed by clicking on DHCP / Server / Setup
IP Maps. See Figure: Dynamic_2 below.
Figure: Dynamic_2
Connection:
Connect the Ethernet cable to the device and to a port on the Server.
Powering On and Status Display:
Power on the client device. The device will request an IP address from the Server. The
Server will offer the client an IP address from the dynamic range. Allow 20 - 30seconds for
the DHCP transactions to finalize.
To view status: Click on DHCP / Server / View Bindings
Figure: Dynamic_3
The Web browser can now be used to view and configure the client device.

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Setting up a Static Range
Using a static IP address enables the DHCP Server to assign a DHCP Client the same IP
address each time the device is connected to a designated port on a Relay Agent.
Basic configuration using Option 82 Relay Agent
The setup for this method is a 2 step process and will be described below.
The first step is to setup the Relay Agent. See Setup Option 82: DHCP Server Switch.
The second step is to setup the DHCP Server. See Setup Option 82: DHCP Server Switch.
Topology:
TX1
192.168.2.100
Example : A connection is made from the Client to a designated port (TX1) on the Relay
Agent.
In this example:
Make configuration on the Relay Agent. See Figure: Option82_1
The Relay Agent has been enabled.
The address of the DHCP server has been specified in the DHCP Server 1 IP as
192.168.2.213.
The Remote ID selected is the IP address of the Relay Agent.
The Relay Status has been enabled. This specifies that the relay agent should send a
request for an IP on behalf of the Client when the Client is connected to port TX1 and
that the VLAN the request will be using is 1.
The default string information provided in the field Other Data will be used (TX1-0001).
Configuration on the Server side should match the configuration on the Relay Agent: See
Figure: Option82_2
The Remote ID’s and Circuit ID’s are the same for the Port selected.
When a request for an IP arrives to the DHCP Server from the Relay Agent, the DHCP
Server will compare the Remote and Circuit ID’s and if they match, an IP will be offered.
In this case the Client will receive the IP address 192.168.2.100.

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Notes:
Other Data : Circuit ID
There are four formats you can use to enter Circuit ID data.
Hex, MAC, IP and String
The default string has particular meaning to an N-Tron Server switch:
(Port-VLAN). For example TX1-0001.
Entering string data in any other format will require you to use the Relay
Agent Type : Generic when configuring the DHCP Server. See Figure:
Option82_2.

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N-Tron Relay Agent Setup Process –Basic Setup Flow
Select Port:
Select:
Relay Status
Enable
Relay
Status
Disabled Assign Local IP
Enabled
Create
Circuit ID
Input Formts:
Hex String
MAC Address
IP Address
Text String
Update
Create
Remote ID
Input Formts:
IP Address
MAC Address
Client ID
Other String
Other Hex
N-Tron DHCP
Relay Agent & Local IP
Setup
Figure: Flow_Relay_Static_Range

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Setup Option 82: Relay Agent Switch
Click on: DHCP / Relay & Local IP / Setup. See Figure: Menu_1
Reference Figure: Option82_1 below.
Set Relay Status to Enabled.
Select the Port the Client will be connected to on the Relay Agent.
Set Relay Status on the Port selected to Enabled.
Set the Circuit ID. The N-Tron default is provided in the text box.
Click Update when finished.
Figure: Option82_1

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N-Tron DHCP Server Static Range Setup Process –Basic Setup Flow
Select Relay
Agent Type
Select
Network
profile
N-Tron Generic
Create
Remote ID
(Use same Port as on
Relay Agent)
Input Formats:
Hex String
MAC Address
IP Address
Text String
Update
Enter IP Address
(Address to be offered to Client)
N-Tron
DHCP Server
Static Range Setup
Select
N-Tron Switch
Type
Add Port
(Port to be Mapped)
Enter VLAN
Create
Remote ID
Input Formats:
Hex String
MAC Address
IP Address
Text String
Select
Port Count
Add Port
(Port to be Mapped)
Apply
Create
Circuit ID
Input Formats:
Hex String
MAC Address
IP Address
Text String
Enter IP Address
(Address to be offered to Client)
Figure: Flow_Server_Static_Range

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Setup Option 82: DHCP Server Switch
Click on: DHCP / Server / Setup IP Maps. See Figure: Menu_1
Click on: Static Range.
Reference Figure: Option82_2 below.
Select the Profile you wish to add this mapping too.
Enter Remote ID: Ex. 192.168.2.1
Click the Add check box corresponding to the port on which the Client is connected.
Fill in the IP Address you would like the relay agent port to receive.
Click Update when finished.
Figure: Option82_2
Mapping:
The resulting mapping from the setup can be viewed by clicking on DHCP / Server /
Setup IP Maps. See Figure: Option82_3 below.
Figure: Option82_3

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Connection:
Connect the Ethernet cable to the port on the Relay Agent you defined in the
mapping.
Powering On and Status Display:
Power on the client device. The device will request an IP address from the Server
through the Relay Agent. The Server will offer the client an IP address based on the
Option 82 Static Mapping. Allow 20 –30 seconds for the DHCP transactions to
finalize.
To view status: Click on DHCP / Server / View Bindings
Figure: Option82_4
The Web browser can now be used to view and configure the client device.

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Setting up a Single IP
IP address allocation is Static and is based on matching Option 61 information received from
a Client. The same IP address will be given each time to a specific Client.
Basic configuration using Option 61 or MAC Address
Topology:
DHCP
Client
Example:
In this example connections can be made to any port on the server or on a switch
connected to the server.
A mapping is created that associates an IP address with the MAC address of the client.
The mapping IP address 192.168.2.110 will be given to the client with the MAC address
00:07:AF:FF:C8:80, that is requesting an IP.
Setup:
Click on: DHCP / Server / Setup IP Maps. See Figure: Menu_1
Click on: Single IP.
Reference Figure: Option61_1
Enter the IP address to be offered to the Client.
Enter the MAC address of the Client.
Click Update when finished.
Figure: Option61_1

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Mapping:
Connection:
Connect the Ethernet cable to a port on the DHCP Server or switch connected to the
Server.
Powering On and Status Display:
Power on the client device. The device will request an IP address from the Server.
The Server will offer the client an IP address based on the Option 61 Static Mapping.
Allow 20 –30 seconds for the DHCP transactions to finalize.
To view status: Click on DHCP / Server / View Bindings
The Web browser can now be used to view and configure the client device.

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Setting up an N-Tron Switch as a Client Device
The N-Tron switch can be configured as a DHCP Client switch or as a Static switch. By
default (Factory Settings) a switch is configured to be Static with a default IP address of
192.168.1.201.
When the N-Tron switch is configured as a DHCP Client, it can be set to change to the
Fallback values if a DHCP server doesn’t give the switch an IP address in approximately 2
minutes by changing the Fallback IP from the Default IP address of 192.168.1.201.
Once the DHCP Client has fallen back to the Fallback values, the DHCP Client will stop
attempting to get a value from the DHCP Server.
Change to the Fallback values will only occur after the initial boot if a DHCP value is
unavailable. If the switch ever obtains a DHCP value during the initial boot, the fall back will
not occur even if the lease is subsequently lost.
The following directions explain how a switch can be configured to be a DHCP Client.
Topology:
Example:
A switch will be configured to power up in DHCP mode ready to receive an IP address when
connected to a server.
Setup:
Click on: Administration / System. See Figure: Menu_1
Click on Modify
Reference Figure: Client_1 below.
Select the IP Configuration: DHCP
Modify Client ID, Fallback IP, Fallback Subnet Mask and Fallback Gateway if Desired
Click on Update when finished.
Click on the Save & Reset Button shown.
The switch will reset and request an IP address. It will receive an address when connected to
a DHCP server.
If the Fallback IP is changed from the default IP of 192.168.1.201 and the DHCP client
doesn’t obtain an IP during the first 2 minutes, fallback will occur to the Fallback values.

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Figure: Client_1