How do I add Subnet Static Routes for Bridge mode?

iPrism provides outbound Internet access via the configured Default Route. When iPrism is installed "in-line", it sits between the Internet facing device (identified with the Default Route field) and internal subnet clients.  The addition of static routes  lets iPrism route self-generated inbound traffic, such as iPrism "block" pages, to internal subnet clients (192.168.0.4, 192.168.0.3 below).   

• Note that in Proxy mode iPrism is NOT between the gateway and clients. The default route device routes inbound return traffic, not iPrism. Therefore adding static routes to a proxy mode iPrism is not necessary.

Without static route information, iPrism will route inbound traffic using the default route (the only route it knows about), which can produce network symptoms such as slowness. If, after receiving traffic back from iPrism the default route device cannot reach the internal client network a "routing loop" will occur such that traffic is delivered back and forth between iPrism and the device. If the default route device has an alternate route back to the internal subnet, the traffic would  be redirected, but delivery may be inefficient. This is easily avoided by configuring static routes  as outlined below.

Configuring Static Routes

The key to configuring static routes is to be clear about which subnets you wish to support, then collect the needed netmask and gateway information. You may need to contact a network administrator to get all the information you need.

For each subnet, identify the Destination Network (i.e., subnet), Mask (netmask), and Gateway.  

• The Gateway(s) that you identify to iPrism are always one hop away, and are always on the same subnet as iPrism. In the diagram above, iPrism is connected to a dumb switch in subnet 192.168.0.0/24.  192.168.0.3 and 192.168.0.4 are smart switches/routers that have routing information to their respective subnet clients. Therefore, in our example, we need to setup static routes  to 192.168.0.3 and 192.168.0.4.

• If the dumb switch was replaced by a Layer 3 Switch or Router, it would only be necessary to setup a single Static Route.

• To implement the example above, 5 static routes for 2 Gateways will be specified in iPrism, resulting in 5 entries in the screen shot below. Perform the following:

1. From the iPrism home page, select System Settings, then Network ID.

2. In the Routing frame, click Static Routes.
   
   

3. Click Add.
   
   

4. To change the range of addresses behind the static route, in the IP field, type the base IP address of the subnet that lies behind the route.
   
   

5. Type a Netmask in the Netmask field. This defines the series of workstations in the remote location that you want to reach.

6. In the Gateway Address field, type the IP address of the Internal router/gateway that connects iPrism to the workstations you specified above.

7. Click OK. The new route displays in the Static Routes frame.

8. Repeat this procedure as necessary to create additional static routes in iPrism. When you are finished, click OK.

9. Click OK again to save your changes and return to the Network ID window, or Cancel to cancel.

10. In the Network ID window, click Save to save your changes, or Revert to cancel.

Static Routes FAQs

You can view routing table information in iPrism, see:

  Checking iPrism Routes

For an additional example including network diagram, see:

iPrism on Networks with Multiple Subnets (PDF)

For examining network addressing, see:

Network/Netmask Calculators