Network Prefix Translation, shortened to NPTv6, is used to translate IPv6 addresses. A common usage for this is to translate global (“WAN”) IPs to local ones. In this regard, it is similar to NAT, although NPTv6 can only be used to map addresses one-to-one, unlike NAT which typically translates one external IP to several internal ones.

NPTv6 routes are listed at Firewall ‣ NAT ‣ NPTv6. New rules can be added by clicking Add in the upper right corner. A quick overview of the fields:


Disables this rule without having to remove it.


Which interface this rule should apply to. Most of the time, this will be a WAN interface.

Internal IPv6 Prefix

The internal IPv6 prefix used in the LAN(s). This will replace the prefix of the destination address in inbound packets. The prefix size specified here will also be applied to the external prefix.

External IPv6 Prefix

The external IPv6 prefix. This will replace the prefix of the source address in outbound packets.


The category this rule belongs to, can be used as a filter in the overview.


A description to easily indentify the purpose of this rule in the overview.