Configuring IP routes settings

You need to set up one or more routing settings to control how IP traffic flows in and out of the IP gateway.

It is important that these settings are configured correctly, or you may be unable to make calls to or from the IP gateway or access the web interface.

To configure the route settings, go to Network > Routes.

On this page:

Port preferences
IP routes configuration
Current IP status

Port preferences

If both Ethernet ports are enabled, it is necessary to specify which port is used in certain special circumstances. Make the appropriate selections described below, click Apply changes to make any changes take effect.

Field	Field description	Usage tips
Default gateway preference	The IP address to which the IP gateway will send packets in the absence of more specific routing (see IP routes configuration). Therefore, it only makes sense to have precisely one default gateway, even though different default gateways may have been configured for Ports A and B. Use this option to decide which port's default gateway configuration to use as the unit's default gateway.	For example, in environments where the IP gateway is connected through Port B to the internet, you will usually choose Port B as the Default gateway preference. Note that in this case, if you have more than one subnet on Port A, you will need to create routes to those subnets clicking Add route on the Network > Routes page.
Name server (DNS) preference	The IP address to which the IP gateway will send requests to look up unrecognized host names in order to determine their corresponding IP addresses. Only one name server (and associated secondary name server) may be used, even though different name servers may have been configured for Ports A and B. Use this option to decide which port's name server configuration to use as the unit's name server.	For example, in environments where the IP gateway is connected through Port B to the internet, you will usually choose Port B as the Name server (DNS) preference.

Field

Field description

Usage tips

Default gateway preference

The IP address to which the IP gateway will send packets in the absence of more specific routing (see IP routes configuration). Therefore, it only makes sense to have precisely one default gateway, even though different default gateways may have been configured for Ports A and B. Use this option to decide which port's default gateway configuration to use as the unit's default gateway.

For example, in environments where the IP gateway is connected through Port B to the internet, you will usually choose Port B as the Default gateway preference. Note that in this case, if you have more than one subnet on Port A, you will need to create routes to those subnets clicking Add route on the Network > Routes page.

Name server (DNS) preference

The IP address to which the IP gateway will send requests to look up unrecognized host names in order to determine their corresponding IP addresses. Only one name server (and associated secondary name server) may be used, even though different name servers may have been configured for Ports A and B. Use this option to decide which port's name server configuration to use as the unit's name server.

For example, in environments where the IP gateway is connected through Port B to the internet, you will usually choose Port B as the Name server (DNS) preference.

IP routes configuration

In this section you can control how IP packets should be directed out of the IP gateway. You should only change this configuration if you have a good understanding of the topology of the network(s) to which the IP gateway is connected.

Configuration of routes is divided into two sections: addition of new routes, and the display and removal of existing routes.

Adding a new IP route

To add a new route, first enter the details using the table below for reference. When you are satisfied with the details entered, click Add IP route to make the addition. If the route already exists, or aliases (overlaps) an existing route, you will be prompted to correct the problem and try again.

Field	Field description	Usage tips
IP address / mask length	Use these fields to define the type of IP addresses to which this route applies. The IP address pattern must be in the dot-separated IPv4 format, while the mask length is chosen from a drop-down list. The mask field specifies how many bits of the address are fixed; unfixed bits must be set to zero in the address specified.	To route all IP addresses in the range 192.168.4.128 to 192.168.4.255 for example, specify the IP address as 192.168.4.128 and the mask length as 25, to indicate that all but the last seven bits address are fixed.
Route	Use this field to control how packets destined for addresses matching the specified pattern are routed. You may select Port A, Port B or Gateway. If the latter option is selected, you must specify the IP address of the gateway to which you want packets to be directed.	Selecting Port A results in matching packets being routed to Port A's default gateway (see Configuring network settings).

Field

Field description

Usage tips

IP address / mask length

Use these fields to define the type of IP addresses to which this route applies.

The IP address pattern must be in the dot-separated IPv4 format, while the mask length is chosen from a drop-down list.

The mask field specifies how many bits of the address are fixed; unfixed bits must be set to zero in the address specified.

To route all IP addresses in the range 192.168.4.128 to 192.168.4.255 for example, specify the IP address as 192.168.4.128 and the mask length as 25, to indicate that all but the last seven bits address are fixed.

Route

Use this field to control how packets destined for addresses matching the specified pattern are routed. You may select Port A, Port B or Gateway. If the latter option is selected, you must specify the IP address of the gateway to which you want packets to be directed.

Selecting Port A results in matching packets being routed to Port A's default gateway (see Configuring network settings).

Viewing and deleting existing IP routes

Configured routes are listed below the Add IP route controls. For each route, the following details are shown:

The IP address pattern and mask
Where matching packets will be routed, with the possibilities being:
- Port A - meaning the default gateway configured for Port A
- Port B - meaning the default gateway configured for Port B
- <IP address> - a specific address has been chosen
Whether the route has been configured automatically as a consequence of other settings, or added by the user as described above.

The default route is configured automatically in correspondence with the default gateway preference field (see Port preferences) and cannot be deleted. Any packets not covered by manually configured routes will be routed according to this route.

Manually configured routes may be deleted by selecting the appropriate checkbox and clicking Delete selected.

Routes behavior with disabled ports

If the default gateway preference is set to Port B and that port is disabled, the default route will be updated automatically to route packets not covered by any manually configured route via Port A.

If a manually configured route specifies Port B and that port is disabled, packets matching that route will not be automatically routed via Port A, but discarded. You should take care to avoid this situation.

Current IP status

This table shows the current default gateway and name server(s) for Ethernet Ports A and B. No fields can be changed, and are provided for reference when configuring the other parameters described in the sections above.

	IP GW 3510
	host: IPGW