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Beginner

whats the source IP router will take from its interfaces IPs during PING ?

Facing a PING issue as described:

A router has 2 IPs on its 2 interfaces :(1)192.168.1.1/24 & (2)2.1.1.2/30;

Now when pinging an external IP from the router, which will be the source IP, the router will add in the packet ?

192.168.1.1/24 or 2.1.1.2/30 ?

below I'm attaching the topology I've createdBGP NULL route.png

2 REPLIES 2
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Engager


which exit next hop IP and outgoing interface  is based on routing table and CEF. do sh ip cef x.x.x.x [detail] to see specific info

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Thanks Martin, for the reply.

I will definitely try your's provided solution w.r.t CEF,

However while searching the NET for a solution,I came through a cisco document regarding the issue.

Its stated [am quoting as in the paper]-->

"When a normal ping command is sent from a router, the source address of the ping is the IP address of the interface that the packet uses to exit the router."

It solves my confusion am facing in the topology shared herein.

==Here from RTX PING is unsuccessful to 32.0.0.1,because, default route is via ser 3/0 alias 2.1.1.2.which is taken as the source add. and not permitted by access list;;

BUT,if source address is selected as 192.168.1.1,in extended PING command.,then PING is SUCCESSFUL,as 192.168.1.0/24 is allowed by access list.

--IS THE CONCEPT OK ?

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