LVS routers under any topology require extra configuration when creating multi-port LVS services. Multi-port services can be created artificially by using firewall marks to bundle together different, but related protocols, such as HTTP (port 80) and HTTPS (port 443), or when LVS is used to cluster true multi-port protocols, such as FTP. In either case, the LVS router uses firewall marks to recognize that packets destined for different ports, but bearing the same firewall mark, should be handled identically. Also, when combined with persistence, firewall marks ensure connections from the client machine are routed to the same host, as long as the connections occur within the length of time specified by the persistence parameter. For more on assigning persistence to a virtual server, see Section 4.6.1, “The VIRTUAL SERVER Subsection”.

Unfortunately, the mechanism used to balance the loads on the real servers — IPVS — can recognize the firewall marks assigned to a packet, but cannot itself assign firewall marks. The job of assigning firewall marks must be performed by the network packet filter, iptables, outside of Piranha Configuration Tool.