MacOS X DNS Management
Today, as bad as it sounds was not a stupid day, merely a day of finding problems from previous stupid days.
There are three core ways to handle ‘personal’ name space management under OsX (listed in order of what I guess could be consider best to worst).
- Run your own DNS server, which in many ways is a good idea (but requires some effort and is made very interesting if you are dealing with real IP space and un-routable IP space [192.168.x.x or 10.x.x.x]).
- Use Host files on the systems which need real name information (this is where I am right about now).
- Edit the local (or network) machines in the NetInfo data base.
The second and third mechanisms are convenient because both offer the ability to setup a nice small name (e.g. foo) instead of typing some big huge mess (you can have a full name and a short name such as foo.baz.bar.long.name.com and foo).
I have an iMac at work which I use for testing (most recently of Applets, Servlets and EJB’s) which is running 10.0.4. I was trying some significant code changes, which I expected to run without a hitch (aka lazy mode, always bites you in the rear). The test application hung every time I ran it. Unfortunately, the app server(s) (JBoss & Tomcat) and all my server code were also there, so I can’t say what is broken. Everything worked fine here a ‘few days ago’ and it had worked at home this morning. Time for some digging…
First I tried some basic stuff. Watch the logs and telnet on the ports in question, make sure the connections are open. Everything seemed in order. Eventually, I paid attention to the data coming back from a probe on 1099 (the port used by JBoss to ‘find’ things). The name looked funny… huh? So I duplicated it. A name was being returned as the address for an EJB which no longer existed. The name registry system was telling my test application to connect to a server name which no longer existed (and the name lookup was timing out). Yikes!
The name rang some alarm bells. We’ve been playing internal net games for some time and early last week I got dragged from one network to another (at which point in time I bitched) to another. I’d twiddled all the important stuff (or so I thought). Remember when I said I was using host files for name resolution? The iMac configuration predated all of that. I think I set it up under DP3 (or maybe DP4), and had been exporting and re-importing this config for a while now. Lo’ and behold, when I got transferred from net to net, I missed the fact that I had a couple of systems (including this one) configured with machine info. . When java applications asked for the complete host name, they got the NetInfo settings which were now very out of date. Everything else seemed to work correctly, but you never know, not really…
10:44:25 PM 
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