I'm at a bit of a loss, I've got a number of SER proxies in use and all are working quite well with one exception.

I've configured the proxies to sit between SIP handsets and a SIP capable PBX. All phones register with the proxy at their location and the PBX makes all requests for phones to the proxy. This normally works well. However, for the phones to be able to place outbound calls, I configured the SER proxy to pass all location lookup failures on to the PBX. The PBX then (seeing the request from a registered location) will place the call out. All of this works fine.

The problem comes when one of the phones is not registered properly with the SER proxy and the PBX requests it. The request fails the location lookup and is sent back to the PBX. To correct this I've tried matching the "src_ip" to see if the request is from the PBX however this doesn't appear to work. I have the following condition in the ser.cfg, shouldn't this stop requests from 1.2.3.4 being sent back to 1.2.3.4?

if (!lookup("location")) {

log(1, "Location lookup failure.");

if (src_ip=="1.2.3.4") || (src_ip=="1.2.3.6") {

log(1, "Request from first server."); sl_reply_error();

} else {

rewritehost("1.2.3.4"); log (1, "Sending request to the first server."); t_on_negative("1"); t_relay(); };

break; };