Twice NAPT Overview

Twice NAPT translates both the source and destination IP addresses.

The private source address is translated by dynamically assigning a public address from a pool and a port number. Multiple private IP addresses can be mapped to the same external address because each private address is mapped to a different port of the external address.

The destination address is translated to the IPv4 address of a private server. This redirects traffic destined to a virtual host (identified by the original destination IP address) to the real host (identified by the translated destination IP address). The destination addresses is translated with a one-to-one static mapping to an address in a pool. Port mapping is not performed for the destination address.

You can also statically translate the destination port by using port forwarding. See Port Forwarding for Next Gen Services.