ICMP echo

[bigdog1175]

I'm trying to trouble shoot a VOIP phone with a vendor and am having trouble and sick of arguing about ping response. I have a 3 site setup Site A (10.0.x.0) is the hub with a VPN to site B(10.0.y.0) and PtP t1 to Site C (10.0.z.0) for the time being I am allowing or at least I think I'm allowing all internal traffic across all 3 sites the issue is this I can ping Site C from either of the 2 locations but I can not ping Site B from Site C and the issue is I had a previously working VOIP phones at Site C that are no longer communicating with the voice server and the phone vendor is arguing that because we can't ping it that's why it's not working, all other network services are working correctly NFS, Citrix, RDP. Is there something that I'm missing causing the router at Site A to block ICMP echo but only in 1 direction?

 

[baddos]

There certainly could be an access-list blocking it or some firewall along the way.

 

[VinceWhirlwind]

Which site is the Voice Server on?

Are the IP phones not on their own subnet, seperate from the Data subnet?

If you can ping something (what?) at site C from site B, and can't ping from something (what?) at site B from Site C, it might help to explain exactly what devices you are pinging to, because Windows firewall will allow pings out but not in, for example.

 

[bigdog1175]

I was pinging router to router and router to server as well as server to router, but it seems I fat fingered an IP a fresh set of ehyes on the config seems to have solved my VOIP problems but still not unable to to ping "all the way around".

 

[Quadratic]

If Site C can ping Site B, but Site B cannot ping Site C, I'd very strongly suspect that either ICMP echos are blocked towards Site C or echo replies are blocked towards Site B.

If you're looking for more help beyond generalities, we can't really confirm exactly where the packets are being dropped based on the info provided but I'd start by tracing through the line of path for that ICMP traffic and look for an ACL or firewall policy.

CCNP, CCDP