Oliver really posed two questions in the original post: he wanted to know about the differences between standard ping and extended ping, and he wanted to know why standard ping failed but extended ping succeeded. Sankar's answer was a good answer to the first question and an indirect answer to the second question.
To really be able to answer the question about why standard ping failed but extended ping succeeded we will need to know some additional information about the routers. But we can guess at the answer based on the symptoms. Based on the fact that standard ping failed but extended ping which specified the source address succeeded I would guess that the remote router has a route to the interface specified in extended ping (I believe the Ethernet interface) but does not have a route to the interface used by standard ping.
If we want to proove that this is the explanation we will need the following outputs:
- show ip interface brief from both routers
- show ip route from both routers.
if we have this we can determine which interface would be used by standard ping and can determine whether that subnet is in the routing table of the other router.
The explanation for this is that by default standard ping will use the IP address of the outbound interface as the source address of the ping packet. If the ping packet gets to the remote router but the remote router does not have that subnet in its routing table then it can not respond and the ping will fail. When using extended ping we have the ability to specify the source address. And if we specify a source address and its subnet is in the routing table then extended ping will succeed.
HTH
Rick
HTH
Rick
