It's in the Apple.com domain, but there's an array of hosts the computer chooses from - sort of client-side round-robin. I imagine they use some sort of load balancing on their end, but it's all kinda non-deterministic. You looking for firewall purposes or something?
Yeah kinda. Our Macs are having problems updating themselves through our Squid 3.0 (on FreeBSD) proxy server. It looks like it's the authentication that's not working for some reason. I would like to add the hosts that Software Update pulls from as proxy exceptions to Squid so they don't need authorisation to succeed. I'm happy allowing apple.com as an exception but I have already done that but to no avail. I also tried looking in the DNS lookup cache to see what was being accessed and the Macs did seem to be contacting akainet.net (or something like that) which looked promising but it's still not working after adding that domain to the exceptions as well.
The long term solution would be to get a Mac server installed and use their equivalent of WSUS but we don't have any Mac servers yet.