I used the SER 0.10.99 from CVS code. I have tested it several days. But I found that it often crashed due to unknow reason. I debugged it with the coredump ser produced. it reports: Loaded symbols for /lib/libnss_dns.so.2 #0 0x00a83755 in relay_reply (t=0xb60abbd8, p_msg=0xffffffff, branch=0, msg_status=408, cancel_bitmap=0xbffced88) at t_reply.c:996 996 DBG("DEBUG: relay_reply: branch=%d, save=%d, relay=%d, msg=%s\n", (gdb) where #0 0x00a83755 in relay_reply (t=0xb60abbd8, p_msg=0xffffffff, branch=0, msg_status=408, cancel_bitmap=0xbffced88) at t_reply.c:996 #1 0x00a771d8 in timer_routine (ticks=1104, attr=0x0) at timer.c:251 #2 0x080825d9 in timer_ticker () at timer.c:146 #3 0x0805ce12 in main_loop () at main.c:1097 #4 0x0805e5da in main (argc=3, argv=0xbffcef04) at main.c:1569 Fortunately I started the SER with logging functions. The log says: 8(5775) DEBUG: add_to_tail_of_timer[7]: 0xb60abcf0 18(5775) DEBUG: retransmission_handler : done 18(5775) DEBUG: timer routine:0,tl=0xb60abd00 next=(nil) 18(5775) DEBUG: final_response_handler:stop retr. and send CANCEL (0xb60abbd8) 18(5775) ->>>>>>>>> T_code=180, new_code=408 27(5784) 0(5757) child process 5775 exited by a signal 11 0(5757) core was generated 0(5757) INFO: terminating due to SIGCHLD 19(5776) INFO: signal 15 received 19(5776) Memory status (pkg): 19(5776) qm_status (0x8108d20): 19(5776) heap size= 1027664 19(5776) used= 28000, used+overhead=55840, free=971824 19(5776) max used (+overhead)= 58848 I have two sip ua, the call must go through the SER. It will crash about several setup procedure. I wonder what happens to the SER. Thanks for your kind help. Best Regards Sun Zongjun