SYMPTOMS

"Could not find mail server for domain" message in the SMTP debug log

CAUSE

Possible causes are:

• A firewall is preventing access to this server
• Ensure that the server that is sending is not registered on any black-lists (see www.dnsreport.com and www.dnsstuff.com)
• Verify that a PTR record is defined for IP Address that mail is being sent from. Some servers will refuse connection if there is no PTR record defined.

RESOLUTION

The resolution for each of the abovementioned possible causes are as follows:

• Test connectivity to the server by attempting to telnet to the server as defined in the following article: http://www.mailenable.com/kb/content/article.asp?ID=ME0200079  If the server is unable to connect, then it most likely will be a firewall blocking issue.
• Check www.dnsstuff.com to see if the server is blacklisted
• Ensure that a PTR record if defined for the IP address.  See: http://www.mailenable.com/kb/content/article.asp?ID=ME020115

MORE INFORMATION

DNS Records to create when hosting mail domains: http://www.mailenable.com/kb/content/article.asp?ID=ME020048

How to set up PTR records under Microsoft's DNS Server: http://www.mailenable.com/kb/content/article.asp?ID=ME020115

How do other mail servers learn about my newly installed mail server?: http://www.mailenable.com/kb/content/article.asp?ID=ME020019

MailEnable DNS diagnostic tool: http://www.mailenable.com/tools/memaillookup.asp