Does anyone know if these two technologies are compatible? I am using CONNMARK to do policy routing. I use it to select which WAN interface the packet will leave the system. It seems that CONNMARK doesn't mark related traffic. This makes it very hard to implement what I am trying to do. My rules are as follows: ${IPTABLES} -t mangle -A PREROUTING --source ${_fip} --destination ${_sip} -p ${_proto} -j CONNMARK --set-mark ${_fwmark} -m mark --mark 0 This rule is what I use to select which traffic goes through which interface. Since state established can't be matched on what initially evoked it (like saying "if this packet is established and was established by FTP from X to Y"). In a NAT situation, how would I route FTP for example so that all the related sessions are routed back to the same interface. I don't want a broad rule that just matches all RELATED rules. Any hints?