iPhone sync issues 1 computer 2 locations

I have two users with iPhone4s. Both are having the same issue. With the company issued laptop on the domain in the office, iTunes recognizes the iPhone and allows it to sync. However the main entity of our company has blocked the appstore and most apple servers from within the domain. However when these same users take the iPhone and laptop home, if the wireless card is turned on the iPhone will not be recognized with iTunes at all. If they turn it off the iPhone will be recognized and allow it to sync. However if iTunes or the iPhone reboot they must turn the wireless off again. Both have brand new installs of iTunes (have been completely uninstalled and reinstalled). One of the phones is on 4.2.1 and I'm not sure what the other one is but it's fresh out of the box without updates yet. The one on 4.2.1 was activated within the office (that's the only step we can do in iTunes within the domain. The other he attempted to activate at home but it wouldn't recognize the phone, but the next day in the office it recognized and activated. I am at a loss on exactly what is the issue and if it's simply that they must turn the wireless off each time. Has anyone else seen the issue? Both of the laptops are Windows XP SP3 with current updates.