HP-UX IPFilter Version 16 Administrator's Guide

When a packet comes in, IPFilter first evaluates the NAT rules. IPFilter rewrites the destination
address and port number based on the NAT rule. IPFilter then evaluates the filter rules. With
the rewritten destination address and port number, the packet matches the pass in rule.
Using the rdr and round-robin Keywords for Load Balancing
You can use the rdr keyword with the round-robin keyword to implement load-balancing
systems and redirect traffic to multiple addresses. Separate the target addresses with a comma.
For example:
rdr lan0 20.20.20.5/32 port 80 -> 192.168.0.5,192.168.0.6 port 8000 round-robin
You can specify only two target addresses in each round-robin rule, but you can configure
two rdr rules for the same interface, for a total of four target addresses. IPFilter will load balance
the packets equally between all four target addresses. For example:
rdr lan0 0.0.0.0 -> 192.168.0.1,192.168.0.2 round-robin
rdr lan0 0.0.0.0 -> 192.168.0.3,192.168.0.4 round-robin
rdr: Redirecting Inbound Packets 61