Not sure how Mailsweeper works as an MTA but I wonder if the recipients server is using sender address verification on inbound mail?
Paul -- Paul Hutchings Network Administrator, MIRA Ltd. Tel: 44 (0)24 7635 5378, Fax: 44 (0)24 7635 8378 mailto:[EMAIL PROTECTED] > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Exchange Discussion > Sent: 09 December 2004 11:24 > To: Exchange Discussions > Subject: Delivering mail to an ISP - refused 550 > > Hi > > We are having problems delivering mail to certain ISP's with > the message > 'This host does not accept mail from domains whose servers 550-refuse > bounces. 550-<[EMAIL PROTECTED]> does not appear to be > valid. Sender > verify 550 failed'. > > We use Exchange 2K and our external mail (incoming and outgoing) is > routed via Mailsweeper for SMTP version 4.3. > > TIA > David > > website: www.guidedogs.org.uk > > > > Registered Office: Hillfields, Burghfield Common, Reading, > Berkshire, RG7 3YG > Registered Charity No. 209617 > A company limited by guarantee > Registered in England Company No. 291646 > > > _________________________________________________________________ > 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.
