Is it just me, or does this question have two correct answers?

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Which Cisco IOS command can be issued on a router to test the connectivity of one interface from another interface on the same router?

A ping ( with no address specified)
B ping (with an address specified)
C tracert
D traceroute

I would think both A & B serve the same purpose, can someone explain to me why A is the ONLY correct answer? Is this just one of those questions where Cisco would prefer you use the extended ping over just issuing ping 10.10.1.24 (for example?

@camron-matthews,

Ok...here's the logic behind it.

• A is an extended ping (as you've stated) that allows you to designate source and destination IP addresses. This is important because pings are directed and need both dst and src for the pings to HIT an address (dst) and a reply address to come back to (src). This allows for the ping to originate from one interface with a destination of another interface on the same router.

• B is just a ping with a destination but what are you returning to? When you ping, e.g. ping gi 0/0 with the IP address of 172.16.10.1 from the router, who is the source interface and source ip address? int g0/0 with 172.16.10.1--that's right the very same interface you're trying to ping. So this will not allow you to ping from ONE interface to ANOTHER interface. It will only allow send data out from that interface from the ROUTER.

Let me know if you have any additional questions.

Fantastic, thank you for the explanation, this makes so much sense now :) I love your guy's knowledge and ability to explain even the simplistic of topics with a complex answer

@camron-matthews ,

I think that's a compliment?! hahahaha
Glad to be a help and glad you're a member!