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Community Member

Default Route

Hi There,

Hopefully someone can help me...

I've a Cisco 2811 router with an HWIC-1ADSL card installed.

Running 12.4(11)T.

Problem is that the FastEthernet 0/0 interface cannot see the internet so I think there is a routing problem.

Configured it from scratch using the basic wizard to try and iron out any issues. The router can see the internet fine from the Dialer0 interface as I've pinged websites by name.

The ethernet interface fails when trying the 'Test Connectivity', it fails with the reason below...

"To test connectivity, SDM tries to ping the configured DNS servers. However, there is no configured route to any of the DNS servers through the selected interface."

There is already a default route set to forward to the dialer0 interface.

Any help would be appreciated as I'm confused as why it's not working!

Hall of Fame Super Gold

Re: Default Route


I think that I see the problem, though I do not quite understand the error message from SDM. I do not believe that it is a routing problem. Access list 101 is applied inbound on the dialer interface so it examines all traffic coming into the router. Looking into that access list the only things that are permitted are DNS responses from the configured DNS servers and 3 ICMP messages: echo-reply (ping), time-exceeded (traceroute) and unreachable messages. All other traffic will be denied.

So I believe that you need to revise the access list to permit other types of traffic. give it a try and let us know what happens.



Community Member

Re: Default Route

I think that the access-list configuration is correct, the "ip inspect DEFAULT100 out" will make dynamic entries in access-list 101 for traffic that has left the router to allow the responses back. (A "sho ip acess" will confirm this by having un-numbered entries at the top of the list).

I think the problem is the way the default route has been configured. The command "ip route Dialer0" relies on the upstream device connected to the Dialer interface having proxy-arp configured. The router assumes that every IP address is connected to the Dialer interface so sends out an ARP request for it.

My guess is that your defualt route should be "ip route"

Dan :-)

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