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SM 16 - large mails delivery problem during SMTP Sessions - 500 command unrecognized followed by 421 Too many bad commands closing transmission channel
Problem reported by Ionel Aurelian Rau - 11/27/2017 at 7:53 AM
Resolved
Hello!
 
Since updating to SM Version 16.3.6535, we`ve had major delivery issues: some of the mails (so far we`ve observed that the larger ones, especially with attachments) get stuck at the "Receiving" status. Watching the SMTP session log for these mails, the following example can be seen:
[2017.11.27] 16:32:28 [IP][8846677] rsp: 220 ServerName | Mon, 27 Nov 2017 16:32:28 +02:00 GMT | Mon, 27 Nov 2017 14:32:28 +0000 UTC | Attention IP - Sending unsolicited commercial or bulk e-mail to this computer network is prohibited
[2017.11.27] 16:32:28 [IP][8846677] connected at 11/27/2017 4:32:28 PM
[2017.11.27] 16:32:28 [IP][8846677] cmd: EHLO SendingServer
[2017.11.27] 16:32:28 [IP][8846677] rsp: 250-ServerName  Hello [IP]250-SIZE 47185920250-AUTH LOGIN CRAM-MD5250-STARTTLS250-8BITMIME250 OK
[2017.11.27] 16:32:28 [IP][8846677] cmd: STARTTLS
[2017.11.27] 16:32:28 [IP][8846677] rsp: 220 Start TLS negotiation
[2017.11.27] 16:32:28 [IP][8846677] cmd: EHLO SendingServer
[2017.11.27] 16:32:28 [IP][8846677] rsp: 250-ServerName  Hello [IP]250-SIZE 47185920250-AUTH LOGIN CRAM-MD5250-8BITMIME250 OK
[2017.11.27] 16:32:28 [IP][8846677] cmd: MAIL FROM:<Sender> SIZE=21565874 AUTH=<>
[2017.11.27] 16:32:28 [IP][8846677] rsp: 250 OK <Sender> Sender ok
[2017.11.27] 16:32:29 [IP][8846677] cmd: RCPT TO:<Receiver>
[2017.11.27] 16:32:29 [IP][8846677] rsp: 250 OK <Receiver> Recipient ok
[2017.11.27] 16:32:29 [IP][8846677] cmd: DATA
[2017.11.27] 16:32:29 [IP][8846677] rsp: 354 Start mail input; end with <CRLF>.<CRLF>
[2017.11.27] 16:32:30 [IP][8846677] rsp: 250 OK <ionel-aurelian rau <Sender>> Sender ok
[2017.11.27] 16:32:30 [IP][8846677] cmd: 5mw
[2017.11.27] 16:32:30 [IP][8846677] rsp: 500 command unrecognized
[2017.11.27] 16:32:30 [IP][8846677] cmd: fagC8ZYZRKZ8ojhdotY+lpupGajv3Bh9MaBPnJ8bZgmmVw3JoWxjubR8b1cNswte3ZnTiu++j6ZM
[2017.11.27] 16:32:30 [IP][8846677] rsp: 500 command unrecognized
[2017.11.27] 16:32:30 [IP][8846677] cmd: 7KYbAmVrPEd9vrfX6Wgz50Nl+6PhPqY/+Pyt9D3tP65Emg99QrZ2f22o7yoEhddrs/zdl6p/v1yR
[2017.11.27] 16:32:30 [IP][8846677] rsp: 500 command unrecognized
[2017.11.27] 16:32:30 [IP][8846677] cmd: tH85fDtWJJenzSvs0H8VR//3V1L6LfJRQv3vr8D7inz1deRnN+QZOhV+qZhq/EXTLyb6ehsSzjcs
[2017.11.27] 16:32:30 [IP][8846677] rsp: 500 command unrecognized
[2017.11.27] 16:32:30 [IP][8846677] cmd: 7JBd0x3qexWqJSlfn6J8Xory4hTlw2i51Xjdm2S85hSfJBrV1IVb76WPSxvx+Vapb4G3AGg3hXZp
[2017.11.27] 16:32:30 [IP][8846677] rsp: 500 command unrecognized
[2017.11.27] 16:32:30 [IP][8846677] cmd: wyOLB1HPLYCu09eePLzlcRnLhkv7W7uI92ru3fkO8/borxw9kWoF0RMgegGWdZhjs/EWS4G2u6Th
[2017.11.27] 16:32:30 [IP][8846677] rsp: 500 command unrecognized
[2017.11.27] 16:32:30 [IP][8846677] cmd: 4WFaOlEenwvVQtuwT83tHMT3f+UKbNPIs94Hl9uhx6I/f3aP8bnuNYsdsGZp7/25eAGJ+3fCPWz/
[2017.11.27] 16:32:30 [IP][8846677] Closing transmission channel: too many bad commands
[2017.11.27] 16:32:30 [IP][8846677] rsp: 421 Too many bad commands, closing transmission channel
[2017.11.27] 16:32:30 [IP][8846677] disconnected at 11/27/2017 4:32:30 PM
Apparently, the sender issues some bad command and SmarterMail terminates the connection after a while. We were receiving emails form the same recipients just fine until before updating. We`ve even doubled the threshold for Bad SMTP Sessions (Harvesting) to no avail.
 
PLEASE HELP AS THIS IS A MAJOR ISSUE AND CAUSING HEAVY DISRUPTION OF BUSINESS!
Matt Petty Replied
11/27/2017 at 8:45 AM
Employee Post
We already have a potential fix and we are testing a build. I will be sure to update the thread as this develops. I will have a build here soon. The build we are testing now fixes an auth match issue as well as an issue with SMTP sessions being reset in the middle of the SMTP Data command which is causing the behavior seen above.
 
We already have active tickets on this, so if you are experiencing the issue. You can wait here for a response. 
Matt Petty
Senior Software Developer
SmarterTools Inc.
Robert Simpson Replied
11/27/2017 at 10:44 AM
+1. Was just about to start a ticket process. I'm also getting "550 From domain must match authenticated domain" errors for e-mails that are clearly coming from proper authenticated users using the correct domain in the FROM address.

We are dead in the water right now between these two issues.
Matt Petty Replied
11/27/2017 at 10:57 AM
Employee Post
We sent off a custom build to customers and waiting to hear back. If you'd like the custom build message me on the community. I may post the link here once I confirm it has been fixed.
Matt Petty
Senior Software Developer
SmarterTools Inc.
Ionel Aurelian Rau Replied
11/27/2017 at 11:37 AM
Please update later today if your custom build fixes the problem. We`ve never needed a custom build until now, but this is really causing us issues. If it does fix it, we`ll need it to be able to resume business tomorrow morning.

Thank you!
P
Patrick Mattson Replied
11/27/2017 at 11:52 AM
I received the patch link from Von, what is involved in applying the patch. Is it a full uninstall or just run the update? Never had to do a patch before.
Matt Petty Replied
11/27/2017 at 12:02 PM
Employee Post
You can uninstall but you should also be able to just install without uninstalling. Whatever is easiest for you.
Matt Petty
Senior Software Developer
SmarterTools Inc.
Matt Petty Replied
11/27/2017 at 12:08 PM
Employee Post
We had a customer that installed this and their spool started flowing again. We've sent this out to a number of people so far and still waiting to hear a resounding "it's fixed". I will provide the build here and if it fixes the issue please let us know.
<Link removed, there is an official update now with the fix>
Matt Petty
Senior Software Developer
SmarterTools Inc.
Ionel Aurelian Rau Replied
11/27/2017 at 12:15 PM
I`ll wait for another hour or 2 and if no one else confirms the fix I`ll bite the bullet and install it too.
Matt Petty Replied
11/27/2017 at 12:21 PM
Employee Post
I've been looking through all the tickets and I've been refreshing the community. As soon as I have a solid answer I can let you know.
Matt Petty
Senior Software Developer
SmarterTools Inc.
Matt Petty Replied
11/27/2017 at 12:31 PM
Employee Post
I just got confirmation from someone here on the community, it is working for them now. Will update as I hear more.
Matt Petty
Senior Software Developer
SmarterTools Inc.
Mike Wiegers Replied
11/27/2017 at 12:32 PM
Matt, I updated to 16.3.6535 at about 8 am CST and didn't realize the problem until 12:30. I have uninstalled and reinstalled version 16.3.6522. What needs to be done with the all the null files in the spool. I haven't received any retried emails from the fail messages during that time.
Matt Petty Replied
11/27/2017 at 12:36 PM
Employee Post
Unfortunately the emails may not retry. I'd select them and move them to another location or delete them all together, making sure that only emails with blank data get deleted. Due to the nature of the problem, the sending server likely thought the data was successfully transferred and thus will not attempt retry.
Matt Petty
Senior Software Developer
SmarterTools Inc.
P
Patrick Mattson Replied
11/27/2017 at 1:08 PM
I tried to apply the patch, but it told me I would need to reboot because the service in use. Stopped the service and tried again, but again it told me I will need a reboot I will not be able to give you an update until tonight.
Robert Simpson Replied
11/27/2017 at 1:18 PM
I had to manually clear about 450 items out of the spool that were dead e-mails with no headers and reset state. I can confirm I am receiving e-mails again.

However, I am still seeing these:
cmd: DATA
[2017.11.27] 13:16:24 [184.176.134.80][2758675] rsp: 354 Start mail input; end with <CRLF>.<CRLF>
[2017.11.27] 13:16:24 [184.176.134.80][2758675] rsp: 550 From domain must match authenticated domain
[2017.11.27] 13:16:24 [184.176.134.80][2758675] rsp: 550 From domain must match authenticated domain
[2017.11.27] 13:16:25 [184.176.134.80][2758675] rsp: 250 OK
[2017.11.27] 13:16:25 [184.176.134.80][2758675] Successfully wrote to the HDR file. (c:\SmarterMail\Spool\SubSpool3\56800688102.hdr)
[2017.11.27] 13:16:25 [184.176.134.80][2758675] Data transfer succeeded, writing mail to 56800688102.eml
[2017.11.27] 13:16:27 [184.176.134.80][2758675] cmd: QUIT
Ionel Aurelian Rau Replied
11/27/2017 at 3:18 PM
OK, I updated to custom build v16.3.6540.15729 and indeed the spool seems to be working again. I also testes with some larger emails (tested up to 28 MB for now) since previously it seems that anything above 4-5MB would have a big chance of locking up in the spool - but now they went through just fine.

However, tomorrow we`ll need to keep an eye on the spool again and see how it handles real traffic.

I also salvaged most of the frozen mails in this way:
- before updating, I shut down the SmarterMail service and I copied all of the files in the Spool folders (the .HDR and .EML ones) to another folder
- I sorted by extension and size and deleted the ones with 0 KB
- I copied all of the .EML files to the Drop folder inside the Spool
- All of the mails were picked up and delivered. Some may be incomplete or have attachments missing, but it`s still better than nothing

Hopefully we`ll not have to deal with this again.. Thank you for the custom build.
Martin Zimmermann Replied
11/27/2017 at 4:09 PM
We also updated to this new version 16.3.6540 and the issue seems to be gone. A Testmail we tried twice before and had the issue was now delivered perfectly.

One other thing seems to be worse again. Speed on Safari and Firefox on Mac is as slow as it was in early September. Dropdown menus open in 3-5 seconds, as it was when we updated from 15.4.6151 to 16.2.6442. At least one customer will cry me a river tomorrow morning. How ever, better slow and steady than fast and faulty.

We also find loads of the following entries in delivery logs since update to 16.3.6535:

DEBUG AddRececipient - isAlias: True; isMailingList: False; isLocalUser: False; deliverLocally: True

Please be aware of the typo "Rececipient"!!
P
Patrick Mattson Replied
11/27/2017 at 7:47 PM
I installed the update, stopped the service, ran the exe, and started the service again (does not appear I needed to reboot), took about 5 minutes. It asked about the web page and I enabled my security back again. Settings -> Protocols -> SMTP In -> Require Auth Match (back to Email address)

Did a test to my Yahoo email test account no issues, have been watching the spool so far so good.

Before I would get a bounce back saying email failed, but it would deliver and it stuck in the queue. My real test will be tomorrow when a customer was trying to receive a large file.

Thank you for the quick response on the update. I will have to hunt around and see if there are other potential issues.
M
Mathew Akoto Replied
11/28/2017 at 12:39 PM
I understand here you're all discussing version 16.x. Can anyone please guide me here to setup the right settings.

1> We are facing issues with 13.0 as when we send emails to outside the domain, it gives us errors as "RSP: 421 4.7.0 Too many connections." Incoming emails delivery are working, no problem. But only the outgoing emails from my domain to external domains having issues. Any suggestions please ?

2> Sometime emails are stuck at spool. Tried forcing emails sometime works and sometime not.

Thanks..
echoDreamz Replied
11/28/2017 at 3:27 PM
Generally we iisreset /stop, wait for the IIS worker process to complete close up shop, then stop the SM service, waiting for the MailService.exe process to also close up completely. We then uninstall, then reboot the server to release anything etc. Then install the update. This has worked for us flawlessly for over a decade.
David Finley Replied
11/29/2017 at 8:05 PM
I was given a slightly later version by support and confirm that this later version fixed the issues I was having with smartermail 16.

<Link removed, there is an official update now with the fix>
http://www.interactivewebs.com
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