Here's a log. OS: Debian Sid, kernel 2.6.26. This happens when FreeSWITCH is started during the boot process from the init scripts, as well as subsequently if it is shut down and restarted. Sometimes it is the internal profile that fails, rather than internal-ipv6, as here. tport_tls_init_master(0x18f6bd0): tls key = /opt/freeswitch/conf/ssl/agent.pem tls_init_context: 140a90a1:SSL routines:(null):(null) tport_listen(0x7fedc0006960): tls_init_master(pf=10 tls/[2001:470:801f::2]:5061): Input/output error nta: bind([2001:470:801f::2]:5061;transport=tls): Input/output error nua: initializing SIP stack failed nua: nua_stack_deinit: entering tport_destroy(0x7fedc0006960) su_epoll_port_deinit(0x18fa810) called 2009-03-24 10:42:12 [ERR] sofia.c:750 sofia_profile_thread_run() Error Creating SIP UA for profile: internal-ipv6 It looks like an operating system issue to me.