1-to-1 NAT maps a public Internet IP to an IP on your local area network (LAN).
If your system does not have this app available, you can install it via the Marketplace.
You can find this feature in the menu system at the following location:
You can map 1-to-1 NAT IPs in one of two ways:
1-to-1 NAT - No Firewall
Some protocols can be finicky behind firewalls. In this case you want to configure 1-to-1 NAT with no firewall (make sure you secure the target LAN system some other way!).
1-to-1 NAT - Selective Ports Open
If you only want to map selective ports, for example the TCP 80 web server port, you can configure particular ports in your 1-to-1 NAT mapping.
1-to-1 NAT - With MultiWAN
If you have Multi-WAN enabled, please review the topic on source-based routes. Each 1-to-1 NAT rule must typically be assigned to an external MultiWAN interface as shown by example below: