Restrictions for Carrier Grade Network Address Translation
-
Asymmetric routing with box-to-box (B2B) redundancy is not supported in Carrier Grade Network Address Translation (CGN) mode.
-
B2B redundancy is not supported on broadband with CGN; B2B is supported on standalone CGN.
-
Broadband is not supported with traditional NAT.
-
CGN does not support IP sessions.
-
NAT outside mappings are disabled automatically when CGN operating mode is configured using the ip nat settings mode cgn command.
-
CGN does not support integration with Cisco Performance Routing (PfR). Commands with the oer keyword are not supported. For example, the ip nat inside source route-map pool overload oer and the ip nat inside source list pool overload oer commands are not supported.
-
The match-in-vrf keyword for intra-VPN NAT is not supported with CGN.
-
If you specify a destination port to configure timeout in CGN mode, the destination port is ignored and the local port is considered for timeout.
-
The ip nat settings log-destination command is not supported in a Box-to-Box High-Availability set up.