cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
387
Views
0
Helpful
1
Replies

NAT Problems

johnakeating
Level 1
Level 1

I am setting up a router that has a T1 and a DSL link

I have configured the interfaces and put the outside and inside for the correct interfaces but I can only get nat working on the T1. I feel as if maybe the router is using to T1 line IP address when trying to send to the DSL and the ISP does not accept them.

interface Loopback1

ip address XX.XX.144.66 255.255.255.192

!

interface Loopback2

no ip address

!

interface FastEthernet0/0

description ####### TO DISTRICT LAN ########

no ip address

duplex auto

speed auto

!

interface FastEthernet0/0.2

description DMZ

encapsulation dot1Q 2

ip address 10.1.1.4 255.255.0.0

ip nat inside

no snmp trap link-status

!

interface FastEthernet0/0.20

encapsulation dot1Q 20

ip address 172.16.1.2 255.255.0.0

ip nat inside

no snmp trap link-status

!

interface FastEthernet0/1

ip address xx.xx.12.4 255.255.255.0

ip nat outside

duplex auto

speed auto

!

interface Serial0/1/0

description T1

ip address xx.xx.159.162 255.255.255.252

ip nat outside

encapsulation ppp

ip route 0.0.0.0 0.0.0.0 XX.XX.12.1

ip route 10.0.0.0 255.0.0.0 10.1.1.1

ip route XX.XX.129.32 255.255.255.240 XX.XX.159.161

ip nat pool DSLPOOL xx.xx.12.175 XX.XX.12.179 netmask 255.255.255.0

ip nat pool T1POOL xx.xx.144.65 XX.XX.144.126 netmask 255.255.255.192

It seems as if I can not have both of these running at the same time. The ACL matches both and then only allows the T1.

How do I run two different NAT on the same router?

ip nat inside source list 2 interface Loopback1 overload

ip nat inside source list 3 interface FastEthernet0/1 overload

1 Reply 1

lejoe.thomas
Level 3
Level 3

Hi John,

You need use route-maps to match NAT ACLs to the appropriate outside interface.

route-map T1

match ip address 1

match interface s0/1/0

route-map DSL

match ip address 2

match interface FastEthernet0/1

ip nat inside source route-map T1 interface Loopback1 overload

ip nat inside source route-map DSL interface FastEthernet0/1 overload

Also add a default-route through the T1 link.

Consider reading the paper below as well

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080950834.shtml

HTH

Lejoe