libnfnetlink (and therefore conntrackd) fails to correctly determine link status

[Andreas Ntaflos]

This bug has been reported and recently fixed in Debian (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=684863) and discussed in <http://www.spinics.net/lists/netfilter/msg53196.html> specifically in <http://www.spinics.net/lists/netfilter/msg53202.html>.

libnfnetlink 1.0.0-1 as used in Ubuntu 12.04 suffers from this bug where it fails to correctly determine the link status of "special" devices such as VLANs or bonds. Therefore conntrackd complains about "[ERROR] no dedicated links available!" when starting, even though a dedicated link is indeed available. As explained this happens especially when using bonding or VLAN devices as interfaces for exchanging synchronisation messages. See this example from conntrackd.conf:

        UDP Default {
                IPv4_address 10.0.6.4
                IPv4_Destination_Address 10.0.6.3
                Port 3780
                Interface vlan62
                SndSocketBuffer 1249280
                RcvSocketBuffer 1249280
                Checksum on
         }

It seems the bug has been fixed in Debian's libnfnetlink 1.0.0-1.1. It should also be included in Ubuntu 12.04.