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how to configure NAT with 3 routers.

sivared0001
Level 1
Level 1

10101010.png

The traffic between the loopback 0 interfaces of R1 and R2 should traverse through R3;

R3 should be configured such that it translate 132.10.10.1 to 171.1.1.1 and 132.11.11.1 to 173.2.2.2

You can do NATTING only R3 router.

After completing the solution you do the verification.

Verification

On R3:

R3#show IP NAT translation

Pro  Inside global          Inside local        Outside local          Outside global
---  ---                    ---                 173.2.2.2              132.11.11.1
---  171.1.1.1              132.10.10.1            ---                    ---



R1# Ping 173.2.2.2 source 132.10.10.1  

It should be ping

and when your ping comes then your R3 result should be change

R3#show IP NAT translation

Pro  Inside global          Inside local        Outside local          Outside global
---  ---                    ---                 173.2.2.2              132.11.11.1
ICMP  171.1.1.1:15          132.10.10.1:15      173.2.2.2:15           132.11.11.1:15
---  171.1.1.1              132.10.10.1        ---                    ---


Note : Run OSPF protocol and you can use only one static route of any devices.

29 Replies 29

balaji.bandi
Hall of Fame
Hall of Fame
how to configure NAT with 3 routers.

the description clearly says that you do NAT in R3, that means , R3 connected to externally.

 

You can use below example, change as per requirement.

interface x/0
ip address y.y.y.y  255.255.255.0
ip nat outside
!
interface x/1
ip address 192.168.1.1 255.255.255.0
ip nat inside
!
access-list 1 permit 192.168.1.0 0.0.0.255
ip nat inside source list 1 interface FastEthernet0/0 overload

BB

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How to Ask The Cisco Community for Help

sssssssssssssssss.png

not working 

To help better, post the config as attachement instead of screenshot.

 

BB

***** Rate All Helpful Responses *****

How to Ask The Cisco Community for Help

not supporting the gns config files to send in attach 

Hello

The NAT solution I provided also shows how to configure OSPF 

Its provides each spoke rtr with a default route from ospf, it also creates two static routes for the nat addressing (required) lastly policy based routing is applied as you only have a single physical interface on the nat router for translation, as such it uses also it own loopback interface for the two nat domains.


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Hi

 What you did so far?

 

Router(config)#ip nat inside source static 132.10.10.1 172.1.1.1 

 

Router(config)#ip nat inside source static 132.11.11.1  173.2.2.2

 

 

 

Router(config)#interface fa×/×

Router(config-if)#ip nat inside

Router(config-if)#exit

 

 

 

 

Router(config)#interface ×/×

Router(config-if)#ip nat outside

 

 

?

i did like you said but not working please check my replies to known my issues

You are using the wrong interface for inside and outside.  I did answer above.

sivared0001
Level 1
Level 1

 

11111111111111111111111111111111111.png

R3 has two interfaces one is e1/0 and loopback0 

so i gave ip nat inside for e1/0 and ip nat outside for loopback0

 

task:

R1# Ping 173.2.2.2 source 132.10.10.1

when i try to ping like above i am not able to ping 

 

when i check nat trasnlations  i am getting only inside global and inside local and not getting outside local and outside global like mentioned in the question.

 I think is the opposite.

Loopback is inside and e 0/1 is outside.

 

Outside is the interface your leave the router.

still getting same error even if i change inside and outside i am not able to ping from R1# Ping 173.2.2.2 source 132.10.10.1

can u check in your gns or packet tracer

Export your GNS3 project and attach here, I can take a look.

But, look, who is going to reply? Have you think about that?

Where the IP address 173.2.2.2 is configured?  As per your topology, you should have one more device with this IP address.

Make sense?

the topology was correct we should not change anything in topology 

translate 132.10.10.1 to 171.1.1.1 and 132.11.11.1 to 173.2.2.2 one is for R1 and one is for R2

 

Note : Run OSPF protocol and you can use only one static route of any devices.

 what about this note, what to with note?

 

 

 

I got it.  Try this:

 

R1

conf t

router ospf 1
network 131.45.43.0 0.0.0.31
network 132.10.10.0 0.0.0.3

wr


R2

conf t
router ospf 1
network 131.45.43.0 0.0.0.31
network 132.11.11.0 0.0.0.3

wr


R3

conf t

router ospf 1
network 131.45.43.0 0.0.0.31
network 132.13.13.0 0.0.0.3

!

 

 

 


interface Ethernet1/0
ip address 131.45.43.3 255.255.255.224
ip nat inside
duplex full
!

!
interface Loopback0
ip address 133.13.13.1 255.255.255.252
ip nat outside
!

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