User's Manual

Configuring GRE, NAT, RIPSO, and BFE Services
2-18
308625-14.00 Rev 00
Starting NAT Synchronization
NAT synchronization allows up to 10 routers configured as peers to share NAT
address translation information. Routers in a synchronized configuration have
up-to-date address translation tables and can handle traffic that may be rerouted to
them if a peer router should shut down or fail.
To configure NAT synchronization, you configure each router as follows:
1.
Start NAT on the router (see “Starting NAT Services” on page 2-11).
2.
Enable synchronization.
3.
Assign the router a unique synchronized router ID. The synchronized router
ID must be unique among all peer routers. You must enter the synchronized
router ID in dotted-decimal notation, but the router ID does not need to be an
actual IP interface address.
4.
Configure the router with information about its synchronization peers,
including the synchronized router ID and IP address for each peer. The IP
address can be any valid IP interface.
Routers in a synchronized configuration must be identically configured for the
following parameters:
• Synchronization port. This value is the TCP port that NAT routers use to
exchange translation updates. If you change it from its default of 670, be sure
to use the same port value for all routers in a synchronized configuration.
• Local and global address ranges. These ranges must be the same on all peer
routers. Static and N-to-1 mappings are not synchronized and can remain
unique for each router.
You can use the BCC or Site Manager to configure NAT synchronization.
Note:
You can configure a NAT router to accept translation updates without
generating updates of its own. To configure a router as a NAT synchronization
peer of this type, you must enable NAT and NAT synchronization on the router,
and include this router in the peer list of other NAT routers. However, you do
not configure address ranges or synchronization peers.