HP-UX IPFilter Version A.03.05.14 Administrator's Guide

Firewall Building Concepts
Using Keep State with UDP
Chapter 468
Using Keep State with UDP
You can configure IPFilter rules for UDP connections using the keep
state keyword. An entry is added to the state table for UDP connections,
the same as with a TCP connection acted on by a rule with the keep
state keyword. For example:
pass out on lan0 proto udp from any to any port 33434><33690
keep state
For more information on using the keep state keyword, see “keep state:
Protecting TCP, UDP, and ICMP Sessions” on page 34 and “Using Keep
State” on page 66.