Even though an e-mail address is not listed in the Sender Filtering on Exchange 2003, the e-mails from this address is not getting through our system.The only way to reverse this is to add the relevant address into Sender Filtering and then remove it again after a few minutes.Once the e-mail address has been removed from Sender Filtering the e-mails from that address then start to come through. Does anyone know of any reason why this happens in the first place and do they have a fix to stop it from happening in the future? The concern is that it is happening to other addresses that we’re not aware of and because we are such a large organisation important e-mails could not be getting through to us that we’re not aware of.

Hi,Can you tell us which NDR the e-mails are bouncing with (the complete error message please).Leif

There no NDR's for the bounced e-mails, in fact there is nothing to state that the e-mail has bounced - either to the sender or the recipient.

On Mon, 4-Jan-10 13:47:30 GMT, Email bouncing from address not inSenderFiltering wrote:>There no NDR's for the bounced e-mails, in fact there is nothing to state that the e-mail has bounced - either to the sender or the recipient. The SMTP protocol log should show you the RCPT TO command and thestatus code returned by your server. If the server refuses the emailwith a 5xx status code it's the responsibility of the transmitting MTAto generate the NDR. If the status code it 4xx then the message will(eventually) time out on the sending MTA and it's the responsibilityof that MTA to generate the NDR.If Exchange accepts the RCPT TO (with a 250 status code) and themessage is accepted (with a 2xx status code sent after the<CrLf>.<CrLf>) then you can start looking at the AV software or anyother anti-spam software running on your system.---Rich MatheisenMCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP