To change these system parameters, you should use the /sbin/set_parms
sehll script.  This script modifies the system configuration file
/etc/rc.config.d/netconf.  set_parms does not backup the netconf file, so
it's a good idea to back it up yourself before running set_parms:

  # cd /etc/rc.config.d
  # cp -p netconf netconf.prev

To print the usage for set_parms, run the script with no arguments:

  # /sbin/set_parms

After modifying netconf, set_parms will ask you whether you want to reboot
the system; this is necessary in order to apply the configuration changes.
You can answer "Yes, Reboot", or you can answer "No, Do Not Reboot" and
reboot at a later time.