[j-nsp] Cannot ping with loopback as the source

[wang yi]

Experts,

I have got router connected to the Internet. I can ping to the Internet with
the default source IP of the /30 SONET IP. When I ping to the same IP with
"source <IP address of lo0.0>", the ping simply hangs there without giving
any output.

Could any one shed any light on this?

thanks and regards,

william