General Routing Question

[mesagreg]

Okay, I know this is probably a stupid question, but here goes...

I have a 2621 with one serial WIC, and two fast ethernet interfaces. The serial connection goes to my new isp, while fa0/0 goes to my lan. I have a dsl router that goes to my existing isp which provides my dns and mail services. All interfaces show lines up and protocols up.

I have my serial interface up and running (thanks to wybnormal), and I want to maintain my connection to the old isp by connecting the dsl router's lan interface to my fa0/1 interface on the 2621.

s0/0 has an address from my new isp, fa0/0 has a private address from my lan with nat configured. I set the ip adress of fa0/1 to an address from my old isp with the appropriate subnet mask. When I show the routes in my 2621 it shows (as expected) that all the networks are directly connected. However, I cannot ping the interface of my dsl router. Furthermore, when I run a traceroute on the address of the old isp's router at the other end of my dsl connection, I find that the packet is going through the serial port that connects me to my new isp. BTW, the gateway of last resort is my new isp's router on the other side of my hdlc connection.

In my simple world, it seems that since the router knows the networks that are attached to it, it should route packets to the appropriate interface based on the destination address. That is, an icmp packet that is destined for the old isp's router should get routed through fa0/1, not s0/0, no matter what the gateway of last resort is.
I'm confused. What am I missing here?

Greg L.

 

[jeter]

WOW, lets put on are thinking caps here!!!! So you have 2 isp's one via the serial interface and a DSL on Fa0/1. Your
gateway of last resort is the new isp. As we all know DSL
is a broadcast usualy through a hub with the pc's pointing
to a gateway of the dsl router. Several questions would have to be asked here to proceed. Is your dsl a router, or a modem ? Is it static or dynamic ? >:O> Jeter@LasVegas.com Remember to pass Cisco's CCNA you need at least an 849 to pass!!!

 

[mesagreg]

The dsl router is a Lucent pipeline. I have 32 static addresses from the old isp.

Greg L.

 

[wybnormal]

You can use policy routing here by either filtering IP address and/or traffic type and then redirect the packets out a specific port. The policy routing will overide the route table to put the packets out the correct port based on the policy.

Mike S
"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[jeter]

You advised that you have a cellpipe dsl with 32 ip's.
can you send a sample config and advise on who your isp is?
Please send to Jeter@LasVegas.com Thanks in advance ! Jeter@LasVegas.com Remember to pass Cisco's CCNA you need at least an 849 to pass!!!

 

[mesagreg]

I didn't think of policy routing....I'll set that up and see what I get. Thanks.

My former ISP is a company called Bluestar. They suddenly decided to pull out of our area, though, which is why we are reconfiguring our router.