IP Forwarding allows a host to effectively act as a router, passing packets from one interface to another.
The default value (HP/UX 10.20 and 11i) is “on” (2), but in many cases this is undesirable from a security point of view.
In order to disable IP Forwarding:
# ndd -set /dev/ip_forwarding 0
And to make this change persistent across reboots:
/etc/rc.config.d/nddconf TRANSPORT[x]=ip NDD_NAME[x]=ip_forwarding NDD_VALUE[x]=0