I downloaded ser 2.0.0-rc1 source code from http://www.iptel.org/ser_2_0_0_release_candidate_1 and install on my Linux step by step according the tutorial on the WEB. When I running SER, I got follow messages: [root@sipmcu ser]# ../../sbin/ser -f ser.cfg Listening on udp: 10.0.0.21 [10.0.0.21]:5060 tcp: 10.0.0.21 [10.0.0.21]:5060 Aliases: tcp: sipmcu.leadtek.com.cn:5060 udp: sipmcu.leadtek.com.cn:5060 *: mytestser.org:* WARNING: no fork mode 0(3078) init_tcp: using epoll_lt as the io watch method (auto detected) 0(3078) Maxfwd module- initializing 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) WARNING: xl_mod_init: more IP 10.0.0.21 not used 0(3078) ERROR: init_tcpudp_sock: bind: Address already in use [98] 0(3078) ERROR: ctl: mod_init: init ctrl. sockets failed 0(3078) init_mod(): Error while initializing module ctl ERROR: error while initializing modules could anybody tell me how about it? Thanks a lot. Regards, Frank