In a Windows Server 2008 domain the on-site domain controller serves as both DNS and WINS server. It is also a DHCP server. One workstation is used as a platform for all admin of the various servers in the domain. All servers are shut down at night after a system-wide backup. Every morning there is a period during which no remote desktop sessions can connect to any of the servers which have IP addresses allocated by DHCP. My strategy is to nail down the IP addresses of these boxes, but I want to understand the problem first. This morning the problem is as follows:
Nslookup and Nblookup both agree on the IP address of the target computer, but when I try to ping the target computer, ping somehow resolves the IP address differently and ping fails. My first indication of the problem was when three different remote desktop sessions all failed to connect. If I wait an hour or so after the servers in question have booted up the problem will resolve itself.
On the workstation that cannot connect I have done IPCONFIG /FLUSHDNS. On the DHCP server I set DHCP to use 30 day leases according to the theory that changing IP addresses somehow cause this problem, but the next morning the problem remains. I have confirmed that no computers are mentioned in any HOSTS or LMHOSTS files. I can't figure out where ping is getting its IP address.
Any ideas?
Best Answer
Nslookup and Nblookup both obtain their data directly from the servers, while ping goes through local resources first, hosts file, DNS cache, then DNS lookup (I may have skipped a step) so if it finds an answer there first, that's what sticks.