May: Check the RFC. You should be able to find the SMTP RFC documents at WWW.IETF.ORG John Matteson; Exchange Manager Geac Corporate Infrastructure Systems and Standards (404) 239 - 2981 Defeat is a state of mind. No one is ever defeated until defeat has been accepted as a reality. To me, defeat in anything is merely temporary, and its punishment is but an urge for me to greater effort to achieve my goal. Defeat simply tells me that something is wrong in my doing; it is a path leading to success and truth. --Bruce Lee -----Original Message----- From: may [mailto:may@xxxxxxxxxxx] Sent: Wednesday, April 17, 2002 9:43 AM To: [ExchangeList] Subject: [exchangelist] Unable to send to some addresses http://www.MSExchange.org/ We have Windows 2K with Exchange @K + service pack2 installed i am facing problem when sending mail to @anydomain.net . I receive the following message " There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <main.acbc.com.eg #5.5.0 smtp;500 Syntax error, command unrecognized>" in general where can i find detail discription for each error hope any one can guide thanks may ------------------------------------------------------ You are currently subscribed to this MSExchange.org Discussion List as: John.Matteson@xxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub')