I am running Exchange 2003 on a Server 2003 machine. Recently have discovered that we had one customer that we could not send or receive emails from. I turned up SMTP logging and sent test to the customer and this is the error message that I got:
Event Type: Error
Event Source: SMTP Protocol
Event ID: 7004
This is an SMTP protocol erro log for virtual server ID 1, connection #288. The remote host "xxx.xx.xxx.xxx", responded to the SMTP command "rcpt" with "550 No such domain at this location (email@example.com) ". The full command sent was "RCPT TO:<firstname.lastname@example.org ". This will probably casuse the connection to fail.
I immediately received an NDR report, it said:
There was a SMTP communication problem with the recipients email server. Please contact your system administrator. <Exchange.ourdomain.com #5.5.0 smtp;550 No such domain at this location (email@example.com)>
This is the only recipient taht we are having trouble with but I need to get this straightened out. I suspect that they are running some reverse lookup? How can I fix this on our side?