Hi all. I can't do a trust between a 2003 domain and an nt 4 domain that are on different subnet, i have modified lmhost file on both server like this: ip address server_name #DOM:domain_name #PRE With this implementation i havent problem on nt domain, so i can perform trusting and trusted but when i try to do that on 2003 server i recive the message that name of domain is not a valid name. And also i cant resolve from 2003 server the netbios name on nt machine instead i can resolve the netbios name of 2003 server from nt server, so i need to change host file implementing ip address and netbios name of nt server to resolve this issues. any idea? Sorry for my very poor english.

Hi, Trusts that are created between Windows NT 4.0 domains and AD DS domains require NetBIOS name resolution. After that, please also configure the firewall for domains and trusts by reading the Microsoft KB article below: How to configure a firewall for domains and trusts http://support.microsoft.com/kb/179442 For more information, please also refer to the following Microsoft KB articles: Trust between a Windows NT domain and an Active Directory domain cannot be established or it does not work as expected http://support.microsoft.com/kb/889030 How to establish trusts with a Windows NT-based domain in Windows Server 2003 http://support.microsoft.com/kb/325874 Regards,Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thank you Arthur_Li for your replay. I resolve the issues adding this line in lmhost file of 2003 server : <ip address> "Domain-name\0x1b" #PRE after that from prompt nbtstat -R and nbtstat -c so i have a new line Name-Domain <1b> unique ip address with this configuration i could enstabilish a two way trust without problem. Bye all.