[Ken Case]

Sounds like a network connectivity issue between you and extremesims, not related to the configuration of the server itself. Are you able to ping downloads.extremesims.com? (In a Terminal window, try "ping downloads.extremesims.com", aborting with Control-C when you've satisfied your curiosity one way or the other. You might also try "traceroute downloads.extremesims.com" to see where that gets you.)