The DNS protocol has been around for decades and is a stable and reliable protocol. Even so, DNS does occasionally have problems. PING is a great tool for DNS server diagnosis, and I tend to use it quite frequently myself. However, sometimes PING just doesn’t give you enough information about the problem at hand. When you need more information about a DNS problem than what PING provides you with, you can always turn to the NSLOOKUP command. In this article, I will show you how to use NSLOOKUP.
For Exchange Server to send Internet mail, the DNS servers that Exchange Server uses for your domain must be able to resolve external domain names. To verify that your DNS servers can resolve external domain names, use the Nslookup tool (Nslookup.exe) if you are running Exchange 2003 on Windows 2000 servers.
Procedure:
- At a command prompt, type Nslookup, and then press ENTER.
- Type server <IP address>, where IP address is the IP address of your external DNS server.
- Type set q=MX, and then press ENTER.
- Type <domain name>, where domain name is the name of an external mail domain, and then press ENTER. The mail exchanger (MX) resource record for the domain that you entered should be displayed. If the MX record is not displayed, DNS is not configured to resolve external domain names.
The following example shows how the DNS server for example.com resolves the IP address of the external domain contoso.com: read more…