How to Verify that Exchange Servers Can Resolve Internal DNS Names
When SMTP queries DNS, it always queries for MX records first. If an internal MX record exists and/or it is incorrectly configured, your internal mail delivery may not work.
Before You Begin
Before you perform the procedure in this topic, read Verifying DNS Design and Configuration.
The SMTP DNS Diagnostic Tool is available for use on Exchange Servers running Microsoft® Windows® Server™ 2003. The SMTP DNS Diagnostic Tool simulates the internal code path of the SMTP service and generates diagnostic messages that indicate how DNS resolution is proceeding.
Run the SMTP DNS Diagnostic Tool on the computer for which you want to verify DNS configuration. Your path should include %WINDIR%\System32\Inetsrv so that the tool works.
The SMTP DNS Diagnostic Tool is included with the Windows Server 2003 Resource Kit Tools and you can downloaded it from the Windows Server 2003 Resource Kit Tools Web page.
Procedure
How to verify that Exchange Servers can resolve internal DNS names
On your Exchange Server, open a command prompt, navigate to the following directory and type the following:
<drive letter>:\WINDOWS\system32\inetsrv
Type the following:
dnsdiag internal host name -v 1
Where internal host name is the fully qualified domain name of another Exchange Server in your organization.
Verify that the correct IP address of the Exchange Server is returned. Your output should look similar to the following:
QNAME = example.microsoft.com Type = MX (0xf) Flags = UDP default, TCP on truncation (0x0) Protocol = UDP DNS Servers: (DNS cache will not be used) 172.16.1.101 Connected to DNS 172.16.1.101 over UDP/IP. Received DNS Response: ---------------------- Error: 9501 Description: No records could be located for this name These records were received: microsoft.com SOA Querying via DNSAPI: -------------------- QNAME = example.microsoft.com Type = A (0x1) Flags = DNS_QUERY_TREAT_AS_FQDN, (0x1000) Protocol = Default UDP, TCP on truncation Servers: (DNS cache will be used) Default DNS servers on box. Received DNS Response: ---------------------- Error: 0 Description: Success These records were received: example.microsoft.com A 172.16.1.106 1 A record(s) found for example.microsoft.com Target hostnames and IP addresses --------------------------------- HostName: "example.microsoft.com" 172.16.1.106.