Products:
708, 709FX, 710FX2, 711FX3, 712FX4, 714FX6, 716, 7010TX, 7012FX2, 7018, & 7506GX2 Series
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).
o Circuit 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.
o Remote 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.
Configuring DHCP Serverand 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
N-Tron DHCP Setup Process –Basic Setup Flow
Getting connected with N-Tron DHCPServer
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
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.
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.
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:
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:
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.
Mapping:
- The resulting mapping from the setup can be viewed by clicking on DHCP / Server / Setup IP Maps. See Figure: Dynamic_2 below.
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
- The Web browser can now be used to view and configure the client device.
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:
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.
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.
N-Tron Relay Agent Setup Process – Basic Setup Flow
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.
N-Tron DHCP Server Static Range Setup Process – Basic Setup Flow
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.
Mapping:
- The resulting mapping from the setup can be viewed by clicking on DHCP / Server / Setup IP Maps. See Figure: Option82_3 below.
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
- The Web browser can now be used to view and configure the client device.
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:
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.
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.
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.
Relay Agent -Stand Alone
Setting up the Relay Agent to obtain a Local IP Address
Topology:
Example:
- This method of obtaining an IP address is quick and easy to setup.
- In this example connecting a Client to Port TX1 of the Relay Agent will cause the Relay Agent to give an IP address of 192.168.2.25 to the Client.
Setup:
- Click on: DHCP / Relay & Local IP / Setup. See Figure: Menu_1.
- Click on Modify button at the bottom of the page.
- Select the Port your device will be connected to on the Relay Agent.
- Click on the Relay Status dropdown box for the port you have selected.
- Click on Assign Local IP.
- Complete the Address in the Other Data column. Ex. 192.168.2.25.
- Click on Update when finished.
Connection:
- Connect the Ethernet cable to the device and to the Port selected in the Setup section.
Powering On and Display:
- Power on the client device. The device will request an IP address from the Relay Agent. The Relay Agent will offer the client the IP that was setup for the particular port. Allow 20 seconds for the DHCP transactions to finalize.
- The Web browser can now be used to view the client device.
Advanced DHCP Server Topologies
Setting up a redundant DHCP Server using 2 N-Rings across N-Link
Topology 1:
Topology 2:
Example:
- This example shows how to setup Server redundancy within an N-Ring and N-Link network.
- Topology 1 shows the Network architecture without the clients.
- Topology 2 is a subset of Topology 1 and shows the Redundant Servers, a Relay Agent with attached Clients. The Relay Agent will be configured to forward broadcast request to both servers and will define Option82 mappings to support the Clients.
Setup:
First Step: Configure N-Link to redundantly couple 2 N-Ring networks
- Reference Figure: Advanced_Redundancy_T1 and the User Manual & Installation Guide for the switch.
- Ensure the Coupler and Control cables are disconnected at this point.
- Get Both N-Rings working with Status OK.
- Configure N-Link Slave: Ensure that the N-Link Slave is set to Auto Configure. Save Configuration.
- Configure N-Link Master: Select the Control and Coupler ports. Save the Configuration.
- Connect the Control Link cable.
- Connect the Coupler Link cables.
- Check N-Link status by selecting the N-Link Status View page.
NOTE: There must be an N-Link aware switch on either side of the Master.
NOTE: There must be a direct link between the Master and Slave Control ports and between the Master and Slave Partner ports. Use of media converters or other switches in these locations is not supported.
Second Step: Configure the DHCP Servers for Redundancy
- The Servers will be configured identically with Option61 Static Mappings.
- Warning: If a Dynamic Range is created, it can only reside on one switch.
- Only one DHCP Server will be configured. The other DHCP Server will receive the DHCP configuration by Uploading from the configured DHCP Server.
- Reference the Basic DHCP setup information above and Figure: Advanced_Redundancy_T1
Configuring one of the DHCP Servers (1)
Enable the DHCP Server, Add a Profile. See: Enabling the DHCP Server and Setting up the DHCP Server Profiles.
Add an Option61 Static entry for each N-Link switch. See: Setting up a Single IP.
- Add Option 82 entries for the Clients A,B,C.
- The resulting mappings are shown below
- Convert your N-Link switches from Static to DHCP in order to use the Mapping created. See section: Setting up an N-Tron Switch as a Client Device. You should see the following in the DHCP Server Binding list for the N-Link switches.
Configuring DHCP Servers (2)
- Download the DHCP configuration from DHCP Server (1) using TFTP. See section Firmware/Config – TFTP.
- Disable DHCP Server on the second server.
- Upload this file to the second DHCP Server. See section Firmware/Config – TFTP.
- If TFTP is not available repeat the process from section: Configuring one of the DHCP Servers (1), on the second Server.
- Enable the DHCP Server on the second server.
- Verify that the Profiles and Mappings on both servers are the same.
Third Step: Configure the DHCP Relay Agent
- Enable the Relay Agent.
- Define the Option 82 data for the Clients.
Connection:
- Connect the Ethernet cable to the device and to the Port selected in the Setup section.
Powering On and Display:
- Power on the client device. The device will request an IP address from the Relay Agent. The Relay Agent will offer the client the IP that was setup for the particular port. Allow 20 seconds for the DHCP transactions to finalize.
- The Web browser can now be used to view the client device.
Firmware/Config–TFTP
The TFTP tab under the Firmware/Config category gives the administrator the ability to upload or download a config file for an N-Tron switch. This allows administrators to backup their configurations to a server offsite in case they need to reload their custom configurations at a later time. It is important not to cycle power on the switch or interrupt the data connection between the TFTP server and the switch while you are uploading/downloading a config file. The switch will not stop working if this does occur, but the administrator will have to retransfer the file. This dialog allows for selection of configuration items to save, and of configurations items to download, if available in the configuration file.
Firmware/Config – TFTP, Continued…
- In order to Download and Upload information from the PC to the switch you will need to download and install a TFTP Server application on the PC.
- We recommend using SolarWinds TFTP Server. You may download if for free from here: http://www.solarwinds.com/products/freetools/free_tftp_server.aspx
- You must also make sure that Pings are enabled on the Firewall. See Note below.
Install and setup the TFTP Server.
The status bar along the bottom of the TFTP Server window shows the TFTP Server root directory and IP address.
The Configuration allows you to enter a directory into which your downloaded file from the switch will be stored. The Upload Configuration on the switch will also access this directory when uploading a new configuration. Security should also be set to both receive and Transmit files.
Notes:
To enable ping in Windows Firewall:
1. Open the Control Panel (from the Start menu. Choose Control Panel; or Settings and then Control Panel).
2. Open Windows Firewall (click Network and Internet Connections then Windows Firewall; or double-click Windows Firewall.
3. Click the Advanced tab.
4. In the ICMP box click the Settings... button.
5. Tick the Allow incoming echo request box.
6. Click on OK and then OK again.
7. Close the Control Panel.
Disclaimer
It is the customer's responsibility to review the advice provided herein and its applicability to the system. Red Lion makes no representation about specific knowledge of the customer's system or the specific performance of the system. Red Lion is not responsible for any damage to equipment or connected systems. The use of this document is at your own risk. Red Lion standard product warranty applies.
Red Lion Technical Support
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