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Ping - Source address not showing up in packets

RishiCSE89
Level 1
Level 1

Hello,

 

I'm pinging a multicast client from Source router,

Source#ping 239.5.5.5 repeat 3 source l0

Type escape sequence to abort.
Sending 3, 100-byte ICMP Echos to 239.5.5.5, timeout is 2 seconds:
Packet sent with a source address of 192.168.10.1 

Reply to request 0 from 30.0.0.2, 72 ms
Reply to request 1 from 30.0.0.2, 136 ms
Reply to request 2 from 30.0.0.2, 136 ms
Source#

But the wireshark capture doesn't show the Source Interface (Loopback 0) ip (i.e. 192.168.10.1) rather the gateway interface IP (i.e. 20.0.0.1), despite of the intended source address shows up in Ping commnad.

mcast.png

Any explanation ?? 

2 Replies 2

kndrkim01
Level 1
Level 1

Check out

https://serverfault.com/questions/741931/pinging-a-host-from-a-router-through-the-selected-interface/918679  

By default, the source IP address in an IP packet originated on the router is the router interface where the packet exits the router. You can override that in a ping command, but it doesn't change which interface the packets use to exit the router.

 

and you probably already know

https://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13730-ext-ping-trace.html  

 

Deepak Kumar
VIP Alumni
VIP Alumni

Hi,

It would be great to share a router configuration. There may many reasons behind the same as configuration issue, bug, etc.

Regards,
Deepak Kumar,
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