Hi!

I could be wrong, but it looks like it'll work if it is directly connected to your ISP. However, it may be a bit more problematic if you are behind a router.

And this is where it has to do with the Mac (which is not terribly clear from the title - SORRY! Can somebody fix it?) - with the Apple Air Extreme router, you can get the external IP using SNMP and then you can post the info to your DDNS provider to update the DNS zone.

It should be noted that you can the exact do the same thing from your Mac desktop*, so if you don't mind keeping your desktop on all the time, just run the script off from cron or from launchd (I don't think you don't need to install additional software - just use curl instead of wget and you should be able to get it working with little modification). Of course, if you are concerned about power consumption, this is where this hint is handy

Then there is using third party option i.e. DNSUpdate. That said, this method should be OS independent, so if you upgrade to the next version of Mac OS X, this most likely will still work, wher as the third party option may be a different story.

*First hint to this site and it's already crashing and burning. :/