08-04-2005 08:49 PM - edited 03-03-2019 10:12 AM
Two C2610 connected via Serial V.35 cables.
R2 router S0/0 IP = 10.0.0.2
R3 router S0/0 IP = 10.0.0.3 (DCE)
On both routers, int s0/0 displays
s0/0 is up, line protocol is up.
However, I ping the IP addresses locally and ping is unsuccessful. What am I missing ? Config of r2 is shown below.
Building configuration...
Current configuration : 651 bytes
!
version 12.3
service config
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname r2
!
boot-start-marker
boot-end-marker
!
enable secret xxx
enable password xxx
!
no aaa new-model
ip subnet-zero
ip cef
!
!
!
!
!
!
!
interface Ethernet0/0
ip address 10.0.0.2 255.0.0.0
half-duplex
no cdp enable
!
interface Serial0/0
ip address 192.168.2.62 255.255.255.0
no fair-queue
!
router rip
network 10.0.0.0
network 192.168.2.0
!
ip http server
ip classless
!
!
!
line con 0
exec-timeout 0 0
08-04-2005 09:12 PM
Please paste the sh int s0/0 output on forum
Jaison
08-05-2005 05:52 AM
Did you configure a "clock rate" on the DCE (R3) Router?
08-05-2005 06:12 AM
Dirk
When you can not ping the local interface it is frequently due to a mismatch in addressing between the two ends of the serial connection.
The reason that a mismatch of addressing can prevent ping to the local interface is because the ping to the local interface generates a ping packet which is actually transmitted over the serial, received by the remote router, and forwarded back over the serial. So if the remote router does not match up addressing with your router then ping will fail.
I notice that you message indicates that the serial addresses are 10.0.0.2 and 10.0.0.3. But the config that you posted shows that the 10.0.0.2 is on the Ethernet not on the serial. It looks like CDP is enabled on the serial interface. So a show cdp neighbor detail would be am easy way to verify whether addressing matches up correctly or not since the remote router IP address is shown in the show cdp neighbor detail output.
HTH
Rick
08-05-2005 10:03 PM
Interesting.
On r2 I did:
...
router rip
network 10.0.0.0
network 192.168.2.0
I did the same on r3.
Then I removed the 'router rip' from r3, and all of sudden ping was successful. It is working now.
09-20-2005 04:57 AM
In regards to "the ping to the local interface generates a ping packet which is actually transmitted over the serial, received by the remote router, and forwarded back over the serial." I've known this to be true for a while now, but why is this done? Is this done only on non-broadcast medium? It doesn't appear that this behavior exists on ethernet connections? Is there a document that describes Cisco's ping workflow as it relates to router architecture? Thanks.
Jason
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