If the host name resolution fails, the next step is to determine whether the problem is the DNS server or lack of a network connection. If the name eventually resolves, you can assume that there is a network connection. If the host name does not resolve, at the command prompt, ping the Microsoft Exchange Server computer by IP address.
Ping Succeeds If pinging the Microsoft Exchange Server IP address works in a timely manner, you have established that a network connection to the server exists.
If a ping of the IP address is successful but a profile checkname fails to resolve the IP address, the RPC binding order might be incorrect. Verify that the RPC binding order includes ncacn_ip_tcp first in the list.
If the ping is unduly slow to respond, you might want to look for such things as an overloaded router, or other network bottlenecks.
Ping Fails If ping fails, there might be a networking issue or a TCP/IP configuration problem that is preventing connection to the Microsoft Exchange Server computer. This problem must be resolved before the client can connect to the server over TCP/IP.