Next Hop IP Address for static routes

[kennethsali]

Hi there,

Looking to know if you can configure any other IP address on a WAN router that is not a Serial interface to be the next hop for as long as it resides on that router as opposed to just the IP Address configured on the other end of the serial connection from that router to another and if so does the subnet in which they are matter at all?

e.g.

Router A

Fa0/0: 192.168.3.1 255.255.255.248

Serial0/0.1: 172.16.30.5 255.255.255.252

Router B:

Fa0/0: 192.168.10.1 255.255.255.248

Serial0/0.1: 172.16.30.6 255.255.255.252

Static Route Configuration on Router A

ip route 192.168.10.1 255.255.255.248 192.168.3.1

as opposed to

ip route 192.168.10.1 255.255.255.248 172.16.30.6

or

ip route 192.168.10.1 255.255.255.248 serial0/0.1

when Routers A & B have a direct serial connection via Frame.

Many Thanks

Ken

[nstringf]

Hi Ken,

The first static route configuation for Router A will not work. If you want the traffic to go via the serial interface, you can't point to the fast internet interface.

These two routes are suitable:

ip route 192.168.10.1 255.255.255.248 172.16.30.6

or

ip route 192.168.10.1 255.255.255.248 serial0/0.1

The next hop tells the router where to go to reach the destination.

FYI,

nstringf

[konigl]

I agree with what nstringf said: you need to point the static route in the direction of the next router hop. Best way is to take the fastest path between the two routers; unless you have an alternate pathway to get there via the LAN side that you didn't mention, router A must go through the serial connetion to get to router B.

Two things to add to this:

1. If you try to enter any of the static routes as shown above, with the remote router's host IP address and the subnet mask, the router will come back to you with an "inconsistent address and mask" error message. If you're trying to point the static route to the specific IP address on the remote router's interface, use mask 255.255.255.255; if you're trying to point the static route to all hosts on that subnet instead then use the subnet ID 192.168.10.0, not the host's .1 address.

2. Don't forget to have a corresponding route on router B, that points back to the LAN side of router A using router A's serial interface IP address as the next hop. Otherwise, if you're on router A's LAN your pings, telnets, etc. to (or through) router B will not be completed because router B won't know where to send the return traffic.