NAT and PAT

NAT and PAT used as a security mechanism to hide host behind another device.

Options are:

NAT one to one dynamic - source internal IP address translated to pool of publicly routeable IP address

PAT one to one dynamic - source internal IP address translated to a single source publicly routable IP but different tcp/udp ports.

NAT one to one static - source internal IP address translated to a static single source publicly routable IP

PAT port forwarding static - static single source publicly routable translated to a internal resource using different ports.

Example of one to one dynamic NAT.  Access rule created to match IP addresses 10.1.0;0 to translate.
G1/0 as outside interface/  G2/0 as inside interface.

Use a IP pool 10.123.0.33 with prefix length of 27.

Example of one to one dynamic PAT.  Translate multiple internal client to single publicly routable IP address.

Example of static one to one NAT.  The internal IP address 10.1.0.25 is statically mapped to global IP address 10.123.0.25.

Example of port forwarding static PAT.   Static IP 10.1.0.50  translate to 10.123.0.25 to the port 80.


Command used is

IP NAT INSIDE SOURCE 10.1.0.50 80 10.123.0.25 80 EXTENSIBLE