ping unreachable from outside to F0/0

Unanswered Question
May 2nd, 2007

It's a 3700 router. I am wondering, icmp ping could not reach to F0/0 from outside. i can ping and telnet to s0/0.

int s0/0 -

int f0/0 -

I do an extended ping within this router. source s0/0 and target f0/0. No Response.

No Access-list configured.

It was working for many years and I can telnet to the F0/0 before. Right now, no response either ping or telnet.

any idea?

I have this problem too.
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royalblues Wed, 05/02/2007 - 07:46

Do you have a route for the Fa subnet from the other end router?


Gerard Gacusan Wed, 05/02/2007 - 07:49


ip route

This is a live network, i'm just giving here a fake ip address but the setup is the same to narrow down the issue.

I can telnet to the s0/0 from outside. All interfaces are UP/UP.

kcgeorge1218 Wed, 05/02/2007 - 07:55

Can u PING the 172.x.x.x interface (Gateway, I guess) while on the 172.x.x.x LAN/VLAN

Gerard Gacusan Wed, 05/02/2007 - 08:01

i think there's something wrong with my ISP. They probably remove routes on their end. I can't route from F0/0 to anywhere (ex.

Gerard Gacusan Wed, 05/02/2007 - 08:08

yes i can ping from host(LAN) to the gateway F0/0.

weird thing, the host could route to outside and internet is fine.

I do an extended ping:

target -

source - FO/0

result - no response

target -

source - s0/0

result - successful

Gerard Gacusan Wed, 05/02/2007 - 09:13

I reload the router and works now ...No problem on the configuration.

One thing that i didn't do is clear ip route *. But, reloading is much helpful. Strange problem.

mohammedmahmoud Wed, 05/02/2007 - 09:19


Please make sure that you've configured keepalive under the ethernet interface.


Mohammed Mahmoud.


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