https://bugs.gentoo.org/484212 Description: SO_REUSEPORT may not exist in running kernel When userspace defines SO_REUSEPORT we will attempt to enable socket port number reuse. However if the running kernel does not support this call it will fail preventing daemon startup. If this call is present but fails ENOPROTOOPT then we know that actually the kernel does not support it and we should continue as if we did not have the call at all. (LP: #1228204) . This patch could be removed from the debian package after jessie release. Author: Andy Whitcroft Bug-Ubuntu: https://bugs.launchpad.net/bugs/1228204 Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=732009 Last-Update: 2013-09-20 Index: avahi-0.6.31/avahi-core/socket.c =================================================================== --- avahi-0.6.31.orig/avahi-core/socket.c 2013-09-20 16:36:50.000000000 +0100 +++ avahi-0.6.31/avahi-core/socket.c 2013-09-20 16:38:23.781863644 +0100 @@ -177,7 +177,8 @@ yes = 1; if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &yes, sizeof(yes)) < 0) { avahi_log_warn("SO_REUSEPORT failed: %s", strerror(errno)); - return -1; + if (errno != ENOPROTOOPT) + return -1; } #endif