Re: Routing a Class C through a modem

Matthew S. Crocker (matthew@crocker.com)
Tue, 15 Oct 1996 11:40:19 -0400 (EDT)

> Specifically:
>
> I'd like to do this with a pm25 and a Cisco 4500, but can't seem to
> get the routing correct. What statements would I
> need to add to the Cisco 4500, and Livingston PM25 to
> route 204.177.135.0 through a portmaster with a 204.177.131.54
> address.

I assume the cisco can already talk to the pm25?

on the cisco
ip route 204.177.135.0 255.255.255.0 204.177.131.54

on the pm

add netmask 204.177.135.0 255.255.255.0
add route 204.177.135.0 <ip address of modem> 1

>
> All network addresses have the prefix 204.177.
>
> -------------------------------
> | CISCO 4500 6 port ethernet |
> ---[]---[]---[]---[]---[]---[]-
> .130 .131 .132 .133 .134 .135
>

^^^^ Do you want 204.177.135 to go through the pm or out the last
ethernet (E5)? You have two routes to the same place... (unless this is
a typo).

> The 204.177.130. goes to the radius server.
>
> The pm25 is on the 131 network
>
> modem -> to 204.177.135.0 network (204.177.135.65
> | is the ip on the 135 router)
> ----------------{ }---
> | Portmaster 25 |
> -----[]----------------
> 204.177.131.57 -> Ethernet

Does this mean that 204.177.135.65 is the ip address of E5 on the cisco 4500?

Why would you want to route through the modem if its already attached to
the cisco?

> How do I route 204.177.135.0 through this one modem port?

What is the IP address of the modem port?

> I hope this is clear.

Not really... Did you have typo's? or are you really trying to build a
double route for the same network? The cisco will always take the
shortest route unless you get into stuff like OSPF and/or BGP-4 routing
protocols.

-Matt