We got big problems with 30 Dell E6440 Laptops and WatchGuard SSL VPN. After connect ssl DNS doesnt respond with out ipconfig /flushdns and ipconfig /registerdns. Okay dns starts respond after 20-30mins. This is not configuration problem. We try with couples HP and clone computers. This problem wont issue those. Those problem computer is cloned Dell factory image with sysprep.
I try to install Win7 MSDN downloaded image and testing SSL connect with that. Everything works fine. ping responds with dns name. I think problem is dell factory image. Tried update drivers and Win7 has latest updates.