SMTP command cut-off
Problem reported by Elazar Broad - September 4 at 7:48 AM
Resolved
Hello -
 After upgrading to the 16.x 6816 build, I am running into an issue where the first character of every SMTP command from an iMac client connecting over port 465 (SMTP explicit SSL) is cut off, like so:
10:06:17 [173.xx.x.189][41842435] rsp: 220 xxxx
10:06:17 [173.xx.x.189][41842435] connected at 9/4/2018 10:06:17 AM
10:06:17 [173.xx.x.189][41842435] cmd: EHLO imac
10:06:17 [173.xx.x.189][41842435] rsp: 250-xxxx Hello [173.xx.x.189]250-SIZE 31457280250-AUTH LOGIN CRAM-MD5250-8BITMIME250 OK
10:06:17 [173.xx.x.189][41842435] cmd: UTH CRAM-MD5
10:06:17 [173.xx.x.189][41842435] rsp: 500 command unrecognized
10:06:18 [173.xx.x.189][41842435] cmd: UIT
10:06:18 [173.xx.x.189][41842435] rsp: 500 command unrecognized
10:06:18 [173.xx.x.189][41842435] disconnected at 9/4/2018 10:06:18 AM
This client has worked just fine, until I upgraded to the 6816 build. I've tested manually using OpenSSL's s_client and I can issue commands just fine. Due to PFS ciphers, I cannot capture and decrypt the traffic on the wire to verify that the commands are being transmitted correctly.
 
Thanks,
 Elazar
 

8 Replies

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0
Paul Blank Replied
This "cut off" looks as if it's part of the problems that others are currently experiencing with IMAP after installing 6816 for both v15 and v16. See other threads.
 
 
0
Elazar Broad Replied
Indeed, I added a comment to the IMAP thread.
0
Matt Petty Replied
Employee Post
Hello,
 
This is indeed related to the IMAP issue. Infact this will affect POP, SMTP, IMAP, and XMPP. We are coming out and testing a build now that should fix the issue. There was code changed that all 4 of those used and it negatively impacted all of them. Stay tuned for another update.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
0
echoDreamz Replied
Matt, does the 6821 build the final build that fixes this?

Christopher

0
Robert Emmett Replied
Employee Post Marked As Resolution
The new build does address this issue as well.  The underlying issue was due to a fix for a potential memory leak with how TCP connections were not being properly disposed.
Robert Emmett
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
0
Matt Petty Replied
Employee Post
Yes,
Our most recent release 6821 fixes this issue and any other issue relating to odd behavior with XMPP, POP, IMAP, and SMTP (they all use the same TCP processing code). We have a formal response and a technical explanation coming out soon that should explain this issue deeper among other things.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
0
echoDreamz Replied
That explains the ~17GB of RAM usage that the MailService process was consuming I guess.

Christopher

0
echoDreamz Replied
As always, Thank you Matt!

Christopher

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