Our exchange system has outgoing smtp service via postini smarthost. Lets say I send a test message to two known good recipients and one problematic recipient. I am logging a single 511 response. (postini logs indicate same) SMTP:511 5.1.1 Invalid recipient: <xxxxxxxxxxx@charter.net> E3210But the NDR returned by our exchange system indicates that all three recipients were not deliverable and gives the same 511 error message for all three including the invalid recipient name. HOWEVERI can perform another test in which I send to the same two known good recipents and intentionally fabricate a bad recipient aka buckethead@myfavoritedomain.com. AND it delivers to the two known good and ndrs (once) for the single bad recipient. i.e. its my belief that this is the correct smtp behaviour. ? Worse we have examples where the error that gets multiplied to everyone on the TO: list is not user or domain specific,1 smtp;530 5.7.1 Client was not authenticated - on relay of: MAIL FROM:<user@ourdomain>>and there may be 20 or more recipients and we can't tell which recipient mail server caused the (multiplied) NDR and so its a process of elimination to try and figure out who is rejecting our connection. So this is our actual problem, I am not so upset that the good recipients don't deliver, its the fact that the smtp (exchange) service doesn't get the 5xx error correctly identified to the correct recipient. So in summary what we have is a combination of our exchange, postini smarthost AND certain recipients. NOT all rejected or bad recipients cause this problem. (which tells me it has something to do with how someone is closing/ending/dropping the connection ? )Or maybe this is really just a feature of exchange, which is what postini is telling me. Any advice would be appreciated.

Hi,Before going on, I would like to confirm what's the version of the Exchange server.The normal behaviour should be only oneNDR was received for the bad recipient when sending one email for more than one recipient which belongs to one domain since indeed only one email was sent out and the receiving server is responsible for separating the email.I suggest we use Pipeline Tracing to record the log of the email to be transmitted in order to ensure no transport agent has modified the message before leaving the Exchange server. How to Enable Pipeline Tracing http://technet.microsoft.com/en-us/library/bb125018.aspxThen send it to me at allensyr2003@hotmail.comThanksAllen

Hi,Im having the same problem with charter.net we do not have there email going through a smarthost, just direct DNS.This is hapening on SBS 2003 (Exchange 2003)This is what the SMTPSVC log looks like:216.33.127.20 OutboundConnectionCommand 3/31/2009 17:16:42 RCPT - TO:<xxxxx@charter.net>216.33.127.20 OutboundConnectionResponse 3/31/2009 17:16:42 - - 511 5.1.1 Invalid recipient: <xxxxx@charter.net> E3210216.33.127.20 OutboundConnectionCommand 3/31/2009 17:16:42 QUIT - -216.33.127.20 OutboundConnectionResponse 3/31/2009 17:16:42 - - 221 2.0.0 imp07 charter.net closing connectionThanks,Steve

Add me to list of people having this problem, and with charter.net addresses only. Also doing direct DNS. Charter says it's not their problem, it's a configuration mistake on our server, but can't tell us what exactly. I'm beginning to think this a charter issue though. Anyone else?