PAP2T is connected to WRT54GL with Tomato. After PAP2T reboots reg suceeds. Next reg fails. Next succeeds again, and so on-off, on-off... I set reg timeout to 120s, and long retry interval to 15s, so now it still in on-off mode, but off is short - it retried after 15s and successfully re-registers. To exclude DNS problem I replaced FQDN with IP - no effect To exclude NAT problem I forwarded both SIP and RTP UDP ports. What else could drive my PAP2T crazy?