Have them telnet from their mail server to yours on port 25 and attempt to send a test message. Any anti-spam products installed on your mailserver or gateways?
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Alex Alborzfard Sent: Thursday, January 13, 2005 4:37 PM To: Exchange Discussions Subject: SMTP Error 500 A customer can receive from, but cannot send email to our domain. He gets a bounce back with the error: "Diagnostic-Code: smtp; 500 Syntax error, command unrecognized" at the end of the message. There is no trace of this in the SMTP logs or Message Tracking. Couldn't find anything useful Googling. What could be causing this? Alex Alborzfard _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Web Interface: http://intm-dl.sparklist.com/read/?forum=exchange To subscribe: http://e-newsletters.internet.com/discussionlists.html/ To unsubscribe send a blank email to [EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with. _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Web Interface: http://intm-dl.sparklist.com/read/?forum=exchange To subscribe: http://e-newsletters.internet.com/discussionlists.html/ To unsubscribe send a blank email to [EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with.
