Hi Michael, > Kernel: Linux base 2.4.22_pre2-gss #1 SMP Wed Sep 24 19:51:11 CEST 2003 i586 Does this kernel by any chance have the USAGI patches applied? I'm running cyrus21-imapd for a while on an IPv6 machine without any problems (and providing service to both IPv4 and IPv6). What does "cat /proc/sys/net/ipv6/bindv6only" tell you? Does it help to set this variable to 0 before starting cyrmaster? --jochen