Hi, in order to mantain TCP conecction with UACs behind NAT the only working solution (AFAIK) is setting register expires value smaller than the time UAC mantains open the TCP connection (value "x"). Certainly, I don't know which is the typical "x" value (i.e. Twinkle 1.2 that suports TCP mantains TCP connection for 32 seconds). Is 30 a good value? Of course, in UDP I use "OPTIONS" keepalive from OpenSer, so I don't need (and don't want) a very small register "expires" value. I just want to set "expires" value to 30 seconds in case of TCP. But "registrar" module seems not to allow me it, I just see: default_expires (integer) min_expires (integer) max_expires (integer) It would be nice if I could set an AVP to set the max expires time in the script, and set itto 30 if "proto==TCP". Is it possible in some way? Thanks a lot for any suggestion. Regards. -- Iñaki Baz Castillo