Make a ip change on a Cisco router

Andrew used Ask the Experts™
Hi Experts,

I need to make a ip address change for a new Web Server on a Cisco 1841 as I dont have much to do with the cisco router but I know a little to get me around. If someone can send me the command or simple instructions on how to change the following ip address below

Here's where I get to I did... copy and paste the line I wanted to change but had trouble when you changed the last octect from 11 to 19 it would come up with the following -

biz(config)#$static tcp 20 20 extendable
% similar static entry ( -> already exists

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you need to issue a no command first (note i'm guessing the begining part as i cant see specifically how you put it)

so (you only need the clear line if the old server is still live and has active translations)

Clear ip nat trans *
conf t
no ip nat inside source static tcp 20 20 extendable
ip nat inside source static tcp 20 20 extendable

and then save your config once you're happy with it
also, as a warning, the clear command will kill off all active translation sessions so any connections to the outside world either way will be cut momentarily.


Hi Evil Himan - thanks for the quick reply... only to that lan address right?

to answer your question the server is live but as it s a web server with only a couple of sites so its ok to be down for a little bit.

Stupid question what is the astrix at the end of Clear ip nat trans *  also is this line item to be in privillaged mode?
all that is in privelleged mode
the * is a wildcard, basically it means to delete ALL active translations.
So this means ALL translations in both directions for all servers and users.

Cisco wont let you delete the NAT configuration if there are any current sessions using it. So try without the clear command but if it spits out an error about the translation being in use then you will need to exit out of configuration mode and clear the translations.

Alternatively, just switch the web server off for a little while before doing the change to drop any translations from being active (not very elegant but neither is the other way.)


Ok that's great will give that a try, thanks.

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