Cisco : IP NAT Inside : re-ordering?

[Andrew Battersby]

Can anyone confirm if you can re-order the "IP NAT Inside" statements on a Cisco router.

For example I have a router with lots of NAT Statements as below:

ip nat pool cust1Mail 8.8.8.8 8.8.8.8 netmask 255.255.255.248

ip nat inside source list DEFAULT_NAT interface GigabitEthernet0/0.112 vrf cust1

ip nat inside source list DEFAULT_NAT interface GigabitEthernet0/0.116 vrf cust2

ip nat inside source list DEFAULT_NAT interface GigabitEthernet0/0.114 vrf cust3

ip nat inside source list cust-Mail-Server pool BroraMail vrf cust3 overload

ip access-list extended DEFAULT_NAT

permit ip any any

ip access-list extended cust-Mail-Server

permit ip host 192.168.16.137 any

Now I want the router to nat the "192.168.16.137" IP out of the "8.8.8.8" address but to do this I would guess I need to make sure the "

"ip nat inside source list cust-Mail-Server pool BroraMail vrf cust3 overload" statement is before the "ip nat inside source list DEFAULT_NAT interface GigabitEthernet0/0.114 vrf cust3" statement.

Is there an easy way to re-order the ip nat inside source statements to make sure this is the case?

Thanks

[cadet alain]

Hi,

why don't you just do like this:

ip access-list extended DEFAULT_NAT

deny ip host 192.168.16.137 any

permit ip any any

Regards.

Alain

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[Andrew Battersby]

I was waiting for that reply

This won't work in this case due to the VRF's Each VRF refer's to a seperate routing table and each routing table could have it's own 192.168.16.137 IP address so this would stop every instance of 192.168.16.137 natting out in each routing table. I could create seperate NAT Access-lists for each VRF and this is in fact what I've done to resolve the issue but I wanted to see if there was specifically a way to re-order the ip nat inside statements to resolve it this way as well.

Thanks

Andy

[cadet alain]

Hi,

yes you're right if you use same ACL for all VRFs then it won't work. I've never heard about NAT statement reordering method.

Regards.

Alain

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