Hello, that should be a DNS problem / connectivity problem / blocked ports problem. Please make sure that ICMP is not blocked and validate connectivity using ping command on IP addresses of the wanted servers. Use conditional forwarders to forward DNS traffic to other domains to other domains' DNS servers. Use nslookup to check DNS resolution. Please also make sure that needed ports for trusts are not blocked: http://support.microsoft.com/kb/179442 Use PortQry v2 for check. Please also validate the trust relationship. This posting is provided "AS IS" with no warranties or guarantees , and confers no rights. Microsoft Student Partner 2010 / 2011 Microsoft Certified Professional Microsoft Certified Systems Administrator: Security Microsoft Certified Systems Engineer: Security Microsoft Certified Technology Specialist: Windows Server 2008 Active Directory, Configuration Microsoft Certified Technology Specialist: Windows Server 2008 Network Infrastructure, Configuration Microsoft Certified Technology Specialist: Windows Server 2008 Applications Infrastructure, Configuration Microsoft Certified Technology Specialist: Windows 7, Configuring Microsoft Certified IT Professional: Enterprise Administrator Microsoft Certified IT Professional: Server Administrator

Hi, our company just purchased another company. We established a 1M BDSL WAN connection between two companys. My company got a domain company1.com. The other company got a domain company2.com. I have set conditional forwarder on our DNS server to forward all company2's dns requests to company2.com's dns server. I can RDP to all company2.com's servers through their fully qualified name but I can not ping their IP address. when I use Active Directory sites and services on company1.com's domain controller to connect comanpy2.com forest, it came up: The domain compay2.com could not be found because: The specified domain either does not exist or could not be found. Could someone shed me the light how to troubleshoot please? Thanks in advance. Maggie

Thanks for all the replies. I checked nslookup company2.com, it comes up the ip address ok. I checked the ports, all ports 389, 135, 445 are blocked. 3389 is not blocked. I guess ICMP is blocked too(I don't know how to check). So it must be it. Thanks heaps everyone:-)

hi Maggie, check out this link on how to enable ICMP echo requests. i suggest enable only the Allow incoming ICMPv4 echo requests http://coreygilmore.com/blog/2009/11/19/enable-icmp-ping-with-the-server-2008-firewall/ link below is for windows 7 but i guess it should work as well on server 2008 http://www.sysprobs.com/enable-ping-reply-windows-7Every second counts..make use of it.

Check the similar thread.. may help you. http://social.technet.microsoft.com/Forums/en-US/winserverDS/thread/72642369-e2f9-4248-b5e2-4fc7ab545fdfThanks, Santosh (MCTS W2K8 AD and SCCM) To Infinity and Beyond

Check for port's are they are open for trust. Hire's the port's: There something wrong with network http://support.microsoft.com/kb/179442

which ip address you are trying to ping at? wan ip or the private ip? have you tried to establish a two way trust between the forest?Every second counts..make use of it.

Hi If you can connect through rdp then it means that network is fine. You could not ping right? Check there must be some rule at the firewall of either end which is blocking ICMP.You can use lot of tools to find list of allowed and blocked ports. For trust relationship check port no.-88(Kerberos),135(Netlogon),389(Ldap) and 445(Microsoft SMB).These port are required for trust relationship.

Thanks, cguan. But our firwall is a Cisco ASA 5510.

Thanks, cguan. But our firwall is a Cisco ASA 5510. Hi Maggie, if that's the case you need to consult your network administrator and you can create an ip access list to allow ICMP protocol echo request. but i don't understand why you need to open a firewall on your cisco router i thought that it's the other party is the one not responding to your ping request. Every second counts..make use of it.

Thanks, cguan. Ping is not issue for us so I wouldn't worry about it as long as I can connect the other forest.