Unfortunately, the Flash Runtime team doesn't maintain the distribution infrastructure (there's a separate distribution organization the repackages our binaries for distribution and manages the hosting). Ultimately, much of it is coming off the Akamai CDN, so there's no guarantee that IPs are going to be consistent, or that the hostnames would remain static over time.
If you're administering an enterprise environment, there are better options for enterprise distribution and update management that would bypass all of that complexity.
Check out the administrator's guide for more details:
Unfortunately our environment is not on a domain which makes distribution much more difficult. We do have LANDesk but we have never been successful pushing out flashplayer updates through LANDesk.
Yeah, that's not ideal. You could still run your own internal update server without installing the player over SCUP/SCM/etc, but you'd need to push an mms.cfg to your clients, and it doesn't really help you out of the first-time download problem. If you pre-configure the machines before they go out to clients, you could probably work around that, but yeah, it seems like a helpdesk nightmare.