Source IP Address Translation Overview

During source IP address translation, the original source IP address, port number, or both are translated to a different number.

JUNOS software performs NAT in the following ways:

• Reverse mapping in static NAT—There is no explicit NAT action in a policy to trigger this type of NAT-src. As long as the traffic matches a “ permit” policy and reverse mapping in static NAT is found on the egress interface, the source IP address will get translated according to reverse mapping.
• Source pool defined on egress interface—When performing source network translation (NAT-src), source pool provides JUNOS software with a supply of addresses from which to draw. When a policy requires NAT-src and references a specific source pool, JUNOS software draws addresses from that pool when translation is performed.