second IP address

[Joli Martinez]

Hello

I need to change the IP's on several switches and routers.  What is the correct procedure for adding a second IP and then removing the old one.  I will need to do most of this remotely so I cant loose access to the equipment.

[Leo Laohoo · Accepted solution]

Old IP address to remove is 1.1.1.1/24.

New IP address is 2.2.2.2/24.

config t

interface vlan 123

ip address 1.1.1.1 255.255.255.0 secondary

ipaddress 2.2.2.2 255.255.255.0

no ip address 1.1.1.1.255.255.255.0

end

[Leo Laohoo]

Thanks for taking the time to rate our posts.  

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

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In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

The correct procedure depends on whether what you're changing will cause you to lose connectivity during the change.  If it doesn't, what Leo posted is fine.  If it does, you can save the necessary configuration changes on the device flash and copy it to the running config.  (You might want to have a reload in # minutes, as a backup.)

[Leo Laohoo]

If it does, you can save the necessary configuration changes on the device flash and copy it to the running config.  (You might want to have a reload in # minutes, as a backup.

The process I've posted is "by the book".  But if you want something cheap-dirty-and-nasty, here's what I would ALWAYS do:

1. Open a text document and put in the lines

• interface vlan 123
• no ip address 1.1.1.1.255.255.255.0
• ip address 2.2.2.2 255.255.255.0

2.  Save the file, say, BLAH.txt

3.  Next, remote into your appliance.  Important to note, if your management IP is what you are trying to change, then do what Joseph has recommended and use the "reload in 5" as a back-out solution.  If it is not, then proceed to #3. 

4.  Remote into the appliance and issue the command "copy tftp://<YOUR MACHINE IP Address>/BLAH.txt run".  Warning:  DO NOT copy the file to your startup-config.  

5.  If everything goes well, cancel the reload and save the config. 

[Joseph W. Doherty]

isclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I just want to warn, that Leo's step 4, if being done across the interface supporting remote access, might disconnect mid process.

To avoid that, again, copy the config snippet to local device flash and then copy from local flash to running config.  This insures statements being applied are not impacted by the interface being modified.