IP Phone registration problems over VPN

[t.schaffner]

We have a Remote site connected over a PIX to PIX (6.3.3) VPN connection with IP Phones directly connected to the PIX. No Routers or Switches are installed at the Remote site. At the Main site we have two CallMangers (3.3.3sr4) clustered.

The IP Phones get all the connection settings from the PIX including the TFTP server address. The display of the IP Phones show "Registering" and the Device / Phone page of the CallManger shows the Phone with an "Unknown" state. The Network settings of the Phone shows that the CallMangers are assigned, but none of them is in a active or standby state.

The Application Event Log of the CallManger shows periodically a "Transient Connection" Error for these Phones.

I can ping the phone from the CallManager and the Round-Trip delay is around 80ms.

Any ideas or did anybody discovered the same problems?

Thomas

[Daniel Baum]

This is a resolvable issue, however, without more data, it is difficult to see what is failing.

This first place I would start is here:

http://www.cisco.com/en/US/products/sw/secursw/ps2120/products_configuration_guide_chapter09186a00800eb727.html

I've also seen some cases where the fixup for SCCP was causing a failure. Removing this fixup and retesting is worth a try.

If this is not useful, I would suggest enabling CallManager detailed traces and review the registration attempt by one of the remote phones to see what is failing.

Dan