Changing the IP On Mac OS X Server, Lessons Learned

Is it common to change a server’s IP? I suppose yes and no. Yes, say you decide to move to a data center or your office moves or you want to configure a server to replace another server already using the IP you want for DNS reasons or you just need to reorganize your subnet. Yes, a change in IP is possible. Apple, thanks for figuring that out. I have been using Mac OS X Server since it first appeared on the scene and the sight of a “wheel” user really jarred me. Until now (Mac OS X Server 10.3.x) changing the IP was difficult at best. I called myself a “professional Mac OS X Server installer” for awhile because of needing to change the IP.

Every new version of Mac OS X Server promised ways of changing the IP with ease. Somewhere along the line, I think with Mac OS X Server 10.2 Apple even included an option in the install to use a temporary IP. Hmm, last week when I configured my Xserve (many times) the option was no longer available. Darn…it worked so well! (not) I had hopes for the new “changeip” (man changeip on OS X Server for more information) command, but like all other attempts to change the IP on my Mac OS X Server it failed, and failed miserably.

I do not really understand what the problem is. I have several Mac OS X clients that run web servers and other server processes and when I change that IP, the OS does not think anything of it. Mac OS X Server however is “industrial strength” and therefore has many more complicated issues. In theory you are can log in as root, type in a command like: “changeip 10.0.0.1 10.0.0.2 oldhost newhost” to change the IP from 10.0.0.1 to 10.0.0.2. I was so sure Apple would not burn me that I spent a day configuring my Xserve and then finished the configuration over Remote Desktop at home so I could come in, log in in single user mode and run the changip command.

I walked in my office, happily rebooted the server in single user mode, typed the command in, and received a NetInfo error. No worries, the error code was no where to be found in Apple’s Knowledge Base(No the link is not incorrect, that is just my way of giving you first hand experience of what I got) NetInfo…another friend of mine. Ok, I thought, maybe something weird happened, I will just restart. Nope, same thing. Ok, so I booted up normally and logged in as root. Bingo! The command did it’s thing…or did it? I could now ping the server on the new IP. I was completely amazed, but with all my history with Mac OS X Server, I had to see it in the GUI to believe it.

I opened System Preferences>Network Settings. The old IP was still in the GUI. Ok…maybe it just needed a restart. Restarted, still the old IP remained. I changed it in the GUI, and the even gave it a restart. Why would I care about the GUI when I could ping? Mac OS X Server and I go way back. Guess what? None of my sites work. Guess what? All the configs come back fine, no errors. Guess what? You still cannot change the IP on Mac OS X Server without some pain. Thank goodness for Carbon Copy Cloner. I ended up just cloning the old server drive and putting that on the new Xserve. So close Apple, so close!