I assume that you're trying to set up some firewall rules or something...
Apple's download servers change on a regular basis. They may recycle some host names, but the IP addresses are changing all the time, and many of them are load-balanced - you'll get the same DNS host name, but you'll connect to a new IP address.
Apple's recommendation for most firewall-related scenarios is to open up the entire 17.0.0.0/16 IP address space. Apple owns that entire range of IP addresses, and that's where all of their traffic will originate from.