First my configuration: I have a laptop that was previously running XP and that had been previously part of my corp domain. I upgraded the laptop to Vista 64 bit and now I can not get the laptop back on the domain. The error that I am receiving is "The format of the specified network name is invalid". The domain name is of the format xxxxx.local. I am doing this remotely through a Windows VPN connection. I can ping both the domain controller and the DNS server from my laptop and NSlookup is showing that the domain name is being decoded properly. I am able to join an xp box to the domain without any issues. So far I have disable TCP/IPv6 on both my network adapter and my VPN adapter. I have put the ip address of my domain controller in as the preferred dns server.Any other ideas? By the way my domain controller and my DNS server are both running Server 2008 and there is also an ISA server in place at my corp. HQ.

Hi, Thank you for posting. Based on my research, I would like to suggest the following: 1. Please ensure that the NetBIOS over TCP/IP is enabled =========================================== 1) Go to Control Panel - Network Connections. 2) Right-Click on the connection and click Properties. 3) Find Internet Protocol (TCP/IP) Version 4 in the list. 4) Click Properties, and then click Advanced. 5) On the Advanced TCP/IP settings windows, go to WINS tab. 6) Under NetBIOS setting, click Enable NetBIOS over TCP/IP, and then click OK. 2. Please enable the File and Printer Sharing on both the client and server sides. 3. Check IPSec. If IPSec is enabled for DNS servers, the client may encounter problems when joining computers to the domain. 4. Check the DNS settings. Please assign the DNS server IP address to the Network connection manually to see if it works. Open an elevated command prompt, type the following command, and then press ENTER: ipconfig /flushdns and then ipconfig /registerdns 5. If you use the wireless connection to join domain, please disable it and use wired connection and try again. If you have more than one NICs, please just leave the one which is in use and disable others. If the issue persists, please run ipconfig /all on both the Windows Vista computer and Windows Server 2008 computer and post the reports to the thread for our further research. Meanwhile, I will share the following information with you: Joining a Windows Vista Wireless Client to a Domain http://technet.microsoft.com/en-us/library/bb727033.aspx Joining a Windows Vista Wired Client to a Domain http://technet.microsoft.com/en-us/library/bb727031.aspx Hope this helps.Nicholas Li - MSFT