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ping on serial interface failure

I am trying to connect a remote site using codex modems and a 14.4k low speed data line. When I connected everything the router on both ends show that the serial interface and the lines are up. My problem is when i ping the serial interfaces from the remote or local router, the success rate is zero, but when i ping the ethernet port either from the local or the remote router I get success rate

ranging from zero to 100 percent. But surprisingly all the high speed lines (64 K) do not experience this ping failure on the serial interfaces either remotely or locally. Would anyone know what could be

causing this problem?

My central routers are both cisco 2600 and all the remote routers are cisco 1601.


Re: ping on serial interface failure

try pinging with a longer timeout. the default is 2 seconds. If you are using the router to ping user extended ping like this


Protocol [ip]:

Target IP address:

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]: <-- try 5 seconds

Timeout in seconds [2]:

Extended commands [n]:

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:


Success rate is 0 percent (0/5)


If it works then your circuit is just too slow for normal tests to work.

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