NAT with routing protocols

From: Ashok CCIE (ashok.ccie@gmail.com)
Date: Tue Jul 10 2007 - 08:41:32 ART


Hi Team,

When NAT is enabled, the routing protocols like BGP, OSPF gets disconnects
as these source addresses gets translated. How to avoid this?

Here is few debug and config? Do we always deny routing protocols when
enabled for NAT?

~~~
!
interface Ethernet0/0
 ip address 3.3.3.2 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 ntp broadcast key 1
!
!
interface Serial2/0
 ip address 1.1.1.1 255.255.255.0
 ip nat outside
 ip virtual-reassembly
 serial restart-delay 0
 no fair-queue
!

!
router ospf 100
 log-adjacency-changes
 network 1.1.1.0 0.0.0.255 area 0
 network 3.3.3.0 0.0.0.255 area 0
 network 0.0.0.0 255.255.255.255 area 0
!
!
!
ip nat pool POOL 10.10.10.10 10.10.10.20 netmask 255.255.255.0
ip nat inside source route-map AA pool POOL reversible
!
access-list 120 deny ospf any any
access-list 120 permit ip 10.10.10.0 0.0.0.255 any
route-map AA permit 10
 match ip address 120
!
~~~~

debug:
R1#deb ip nat de
IP NAT detailed debugging is on
R1#
Jul 10 11:26:39.971: NAT: i: ospf (1.1.1.1, 0) -> (224.0.0.5, 0) [967]
Jul 10 11:26:39.971: NAT: s=1.1.1.1->10.10.10.10, d=224.0.0.5 [967]
Jul 10 11:26:49.971: NAT: i: ospf (1.1.1.1, 0) -> (224.0.0.5, 0) [969]
Jul 10 11:26:49.971: NAT: s=1.1.1.1->10.10.10.10, d=224.0.0.5 [969]

Thanks,
Ashok



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