Users are receiving about 95% of their messages from sending SMTP servers. Intermittently, sending SMTP servers send the Exchange 2010 Server a SMTP RSET command for no apparent reason. The RSET Command (by SMTP specification) causes the Exchange 2010 Server
to drop the message. The sending SMTP servers then do not resend the message after asking the Exchange server to drop the message. This means the message is marked as Sent by the sending servers but the dropped messages never show up in the users' Outlook
inbox.
Exchange 2010 Version 14.3 (Build 123.4)
Roles: Hub Transport, Client Access, Mailbox
What is going on?
Exchange Receive Connector log showing a RSET example:
2014-07-17T12:47:07.370Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,1,10.80.120.15:25,65.99.255.73:53479,*,SMTPSubmit SMTPAcceptAnySender SMTPAcceptAuthoritativeDomainSender AcceptRoutingHeaders,Set Session Permissions
2014-07-17T12:47:07.370Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,2,10.80.120.15:25,65.99.255.73:53479,>,"220 vpn.a1expediting.com Microsoft ESMTP MAIL Service ready at Thu, 17 Jul 2014 08:47:06 -0400",
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,3,10.80.120.15:25,65.99.255.73:53479,<,EHLO inbound37.exchangedefender.com,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,4,10.80.120.15:25,65.99.255.73:53479,>,250-vpn.a1expediting.com Hello [65.99.255.73],
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,5,10.80.120.15:25,65.99.255.73:53479,>,250-SIZE 52428800,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,6,10.80.120.15:25,65.99.255.73:53479,>,250-PIPELINING,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,7,10.80.120.15:25,65.99.255.73:53479,>,250-DSN,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,8,10.80.120.15:25,65.99.255.73:53479,>,250-ENHANCEDSTATUSCODES,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,9,10.80.120.15:25,65.99.255.73:53479,>,250-AUTH,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,10,10.80.120.15:25,65.99.255.73:53479,>,250-8BITMIME,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,11,10.80.120.15:25,65.99.255.73:53479,>,250-BINARYMIME,
2014-07-17T12:47:07.480Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,12,10.80.120.15:25,65.99.255.73:53479,>,250 CHUNKING,
2014-07-17T12:47:07.511Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,13,10.80.120.15:25,65.99.255.73:53479,<,MAIL FROM:<a1expediters@aol.com> SIZE=165270,
2014-07-17T12:47:07.511Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,14,10.80.120.15:25,65.99.255.73:53479,*,08D16FD38F3D3355;2014-07-17T12:47:07.370Z;1,receiving message
2014-07-17T12:47:07.511Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,15,10.80.120.15:25,65.99.255.73:53479,>,250 2.1.0 Sender OK,
2014-07-17T12:47:07.558Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,16,10.80.120.15:25,65.99.255.73:53479,<,RCPT TO:<jeewan@a1expediting.com> ORCPT=rfc822;jeewan@a1expediting.com,
2014-07-17T12:47:07.558Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,17,10.80.120.15:25,65.99.255.73:53479,>,250 2.1.5 Recipient OK,
2014-07-17T12:47:10.496Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,18,10.80.120.15:25,65.99.255.73:53479,<,RSET,
2014-07-17T12:47:10.496Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,19,10.80.120.15:25,65.99.255.73:53479,>,250 2.0.0 Resetting,
2014-07-17T12:47:10.559Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,20,10.80.120.15:25,65.99.255.73:53479,<,QUIT ,
2014-07-17T12:47:10.559Z,A1-S1\Windows SBS Internet Receive A1-S1,08D16FD38F3D3355,21,10.80.120.15:25,65.99.255.73:53479,>,221 2.0.0 Service closing transmission channel,
Daniel