Renumbering IPs

Hi all,

Can anyone point me to some sort of documentation on what’s required to renumber a box running Virtualmin GPL? I was informed today that we’re switching ISPs this weekend (gah!!!) and I have to take care of renumbering the network. Here’s the real kicker - I have to do this remotely!

I can deal with changing the IPs on the linux side of things, but I don’t know if it’ll mess anything up in webmin or virtualmin if I just change them in linux, then try to update things in web/virtualmin. There’s seven IPs on the box, with one as the shared and the rest dedicated to individual virtualmin servers.

Is there a howto somewhere on this? A quick 'net search didn’t turn up very much, and I don’t have time to dig very deep, unfortunately.

Thanks for any pointers you can throw my way!


Changing the IP address is oddly straight forward!

To do that, all you have to do is go into Addresses and Networking -> Change IP Addresses, and Virtualmin will handle updating all the config information for your various domains.

Will that do what you’re after?


Sounds good! I’m going to try and throw together a test environment today and test it out. The main thing is that I’m doing it remotely, so it’s gotta work on the first try.

Ok, I think I have the process worked out. Seems to be doing the trick on my test box, but that’s not really saying a lot. I threw it together fast and haven’t really had any time to do a thorough and proper test. Fingers are crossed. I’ll report back how it goes on the production machine after all is done, which might be tonight, or maybe tomorrow.

So far, everything is working as expected after the switch. For the benefit of those needing to do the same thing (and for clarity), we were switching ISPs and needed to renumber our Virtualmin box that had multiple IPs and a lot of domains on it, including some with SSL/private IPs. Here’s the process I used:

  1. Webmin -> Networking -> Network Configuration -> Routing and Gateways -> Boot time configuration
    Set new default gateway and save. Do not change the Active configuration.

  2. Webmin -> Networking -> Network Configuration -> Network Interfaces -> Activated at Boot
    Edit each interface with the new and proper information, but DO NOT APPLY the configurations.

  3. Virtualmin -> Addresses and Networking -> Change IP Addresses
    Change IP address of shared servers.

  4. Reboot.

  5. Login using new IP address.

  6. Select a server with a Private IP address.

    6a. Edit Virtual Server -> IP address and interfaces
    Select “Remove now” under “Virtual interface” and click “Save Virtual Server”.

    6b. Edit Virtual Server -> IP address and interfaces
    Select “Create now with IP” under “Virtual interface” and enter the new IP for that private server. Check the “Already active” box if the interface is already configured. Click “Save Virtual Server”.

    6c. Repeat step 6 for each private server.

  7. Virtualmin -> System Information -> Refresh system information

  8. Virtualmin -> System Information -> IP Address Allocation
    Verify that all IPs and servers are correct.

That was it! Worked out to be fairly easy, which is nice considering how little time I had to plan & implement the change. I would have liked more time to set the TTL for the domains being switched to something tiny, so it would have been a more seamless switch for the internet at large, but all things considered, it went quite well.