Routing Administration

This section describes how to configure the Netra server as a router.

Routing is the mechanism by which systems on different networks can communicate with each other. Each network usually has at least one system called a router. A router is a system that is connected to multiple networks; it maintains information that defines routes between host systems and networks.

The Netra system can be configured as one of the following:

• A dynamic router

• A static router

• Not a router

Dynamic Router

A dynamic router relies on information broadcast from other routers to update its routes and reflect changes in the network topology. It also broadcasts this information to other dynamic routers.

Dynamic routers are typically required when systems act as gateways between networks or within large networks where route information is constantly changing. The Netra server supports the following dynamic routing protocols:

• The Xerox NS Routing Information Protocol (RIP)

• The ICMP router discovery protocol

If client host systems are required to use the dynamic router, they must either run programs that can communicate using these protocols, or they must specify the dynamic router as a default router.

When the Netra server is configured as a dynamic router, broadcasting RIP information over point-to-point (PPP) links can be enabled or disabled. If additional PPP links are defined after the dynamic router is configured, you must reconfigure the dynamic router to ensure that it is aware of the new links.

To Configure the Netra System as a Dynamic Router

1. From the Main Administration page, under "Network Connection Administration," click Routing.

   The Routing Administration page is displayed.

2. Click Configure dynamic router.

   The Dynamic Router Administration page is displayed.

3. Complete the form using the information in the following table.

   Table 7-6 Dynamic Router Administration

   Option	Description
   Host/Net	Specify if a destination address is a Network or a Host. If a value of "net" is entered incorrectly, the system attempts to add the routing entry as a "host."
   Destination Address	Network/Host address to which information is routed.
   Gateway Host Address	Host address of the gateway used for accessing the destination address. If the router is unreachable when this form is configured, it is not used for routing until dynamic routing is reconfigured or the Netra system is restarted.
   Hop Count	A value of 0 or greater. 0 means the Netra server is the router; a value greater than 0 means that another system is the router.
   Status	Active or Passive. Gateways marked "active" are removed from the routing information if they become inaccessible. Gateways marked "passive" are part of the routing information until explicitly removed. Routes to passive gateways are also not broadcast to the other systems on the network.
   Dynamic Routing Information over Point-to-Point Links	Enables or disables RIP over PPP links. Choices: Yes or No.

4. Click OK.

To Modify a Dynamic Router

1. From the Main Administration page, under "Network Connection Administration," click Routing.

   The Routing Administration page is displayed.

2. Click Modify dynamic router.

3. Complete the form using the information in Table 7-6.

Static Router

A static router relies on the manual addition of routes. Routing information is not exchanged with other routers.

Static routers are typically used in very stable, simple networks. An example of such a network would be a single LAN connected to the Internet or to another network over a PPP link.

If machines on the LAN require a static router, it must be specified as a default router.

To Configure the Netra System as a Static Router

Before using static routing over PPP links, configure a PPP connection to the remote host using "Modem Administration", and add a static route to the remote host's host address (IP address).

1. From the Main Administration page, under "Network Connection Administration," click Routing.

   The Routing Administration page is displayed.

2. Click Configure static router.

   The Static Router Administration page is displayed.

3. Complete the form using the information in the following table.

   Table 7-7 Static Router Administration

   Option	Description
   Default Router Host Address	Host address of the default router for the network.
   Host/Net	Specify whether a destination address is a Network or a Host. If a value of "net" is entered incorrectly, the system attempts to add the routing entry as a "host."
   Destination Address	Network/Host address to which information is routed.
   Router Host Address	Host address of the router used for accessing the destination address.
   Hop Count	A value of 0 or greater. 0 means the Netra server is the router; a value greater than 0 means that another system is the router.

If a host address is unreachable at the time of configuration, it is accepted with a warning that the route cannot be accessed. To activate the route once it can be accessed, restart the Netra System, or reconfigure he static router.

To Modify a Static Router

1. From the Main Administration page, under "Network Connection Administration," click Routing.

   The Routing Administration page is displayed.

2. Click Modify static router.

3. Complete the form using the information in Table 7-7.

Setting a Default Route Over a PPP Link

If you require a default route over a PPP link, choose one of the following options:

• If both local and remote host addresses are statically assigned, you can use either of them as the default route.

• If the remote host address is dynamically assigned, use the local host address as the default route.

• If the local host address is dynamically assigned, use the remote host address as the default route.

If both the local and the remote host addresses are dynamically assigned, you cannot use a default route over a PPP link.

Not a Router

A non-gateway system need not be a router in networks that already have dynamic routers. The Netra server listens for dynamic routers to broadcast route information using the RIP and the ICMP router discovery protocols.

To Configure the Netra System as Not a Router

Once the Netra server is already configured as "not a router," this option is not displayed.

1. From the Main Administration page, under "Network Connection Administration," click Routing.

   The Routing Administration page is displayed.

2. Click Turn off routing, then confirm the operation.