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Using NAT during Network Transition

We are planning to replace a few servers within our network, and I am trying to configure our Catalyst 6009 to use NAT to translate the target IP address to the IP addresses to the new servers. But I also need to be able to connect to the new servers directly.

I have installed a PC on vlan 24, the original server on vlan 50 (172.30.50.230) and the new server on vlan 51(172.30.51.230).

With the configuration shown below, when I telnet from the PC to the old server (172.30.50.230) I get connected to the new server (172.30.51.230) as expected.

The problem is that I cannot telnet directly into the new server (172.30.51.230), although ping and traceroute go through to the correct destination.

Is there another command line I need to enter to enable NAT to accomplish this or is there another method I could use instead?

I know I am missing something really simple, so if someone could let me know, that would be really helpful.

interface vlan 24

ip nat outside

interface vlan 50

ip nat outside

interface vlan 51

ip nat inside

exit

ip nat inside source static 172.30.51.230 172.30.50.230

TIA

Dean Scrim

Comms Engineer

3 REPLIES
New Member

Re: Using NAT during Network Transition

This is very complicated process - it involves thorought knowledge of the network topology. Call me so I could discribed to you more...

router1#

Loopback45

ip add xxx.xxx.xxx.xxx mask xxx.xxx.xxx.xxx

inter vlan???

ip policy route-map nonat???

ip nat in or outside

access-lists 145 permit ip xxx.xxx.xxx.xxx 0.0.0.xxx host xxx.xxx.xxx.xxx

access-lists 146 permit ip xxx.xxx.xxx.xxx 0.0.0.xxx host xxx.xxx.xxx.xxx

ip nat in/outside source static xxx.xxx.xxx.xxx 0.0.0.xxx extendable,

route-map nonat1 permit 10

match ip address 145

set interface Loopback45

router2# you will go to the same some similar process or the opposites informations.

it will solve your issues like magic!!!

the router is confused with less info you providing - this will explecitely tell the router(s) what to do with the packets...

Layer3(msfc) blade only!!!

IOS MSFC Software (C6MSFC-JS-M), Version 12.1(4)E1 or above.

-Benjie203.317.5132

New Member

Re: Using NAT during Network Transition

Benjie,

Thanks for the tip, I have been trying to configure the routers as you suggested but I have not had to set up access-lists before so this is all new to me.

In the line

access-lists 145 permit ip xxx.xxx.xxx.xxx 0.0.0.xxx host xxx.xxx.xxx.xxx

should I use

access-lists 145 permit ip 172.30.50.0 0.0.0.255 host 172.30.51.230

We are using Cisco Internetwork Operating System Software

IOS (tm) MSFC2 Software (C6MSFC2-IS-M), Version 12.1(2)E

TIA

Dean

New Member

Re: Using NAT during Network Transition

Dean:

It should work...The host resides in the same segment with this router interface, correct? If then, try that.

Have fun :-)

-Benjie

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