If the number of free NAT entries is critically low, the system should be investigated for a possible leak.

vcadmin@vcg1-example:~$ sudo /opt/vc/bin/getcntr -c natd.nat_shmem_free_entries -d vcgwnat.com
993408
vcadmin@vcg1-example:~$

Reboot the Gateway to clear all assigned NAT entries. Restarting the services has no effect on NAT entries.