[SOLVED in 8536] - New SmarterMail 8524 forcibily reject every SMTP connection with NULL sender. Is this a BUG?

Problem reported by Gabriele Maoret - SERSIS - 5/7/2023 at 12:38 AM

Resolved

New SmarterMail 8524 forcibily reject NULL sender.

I think this can cause issues, at least with antispam gateways.

I discovered this issue with my Fortimail gateway.

Although I was lucky and found a workaround for my Fortimail Gateway (https://portal.smartertools.com/community/a95345/solved-blocking-problem-after-8524-no-incoming-mails-from-fortimail-gateway_-forced.aspx ), I think this is a bug that can affect many other users and situations.

Please review it.

Example:

13:11:19.143 [MY FORTIMAIL IP][7707961] rsp: 220 mail.CUSTOMER.it

13:11:19.143 [MY FORTIMAIL IP ][7707961] connected at 05/05/2023 13:11:19

13:11:19.143 [MY FORTIMAIL IP ][7707961] Country code: FR

13:11:19.223 [MY FORTIMAIL IP ][7707961] cmd: HELO fortimail.MYSERVER.com

13:11:19.223 [MY FORTIMAIL IP ][7707961] rsp: 250 mail.CUSTOMER.it Hello [MY FORTIMAIL IP ]

13:11:19.254 [MY FORTIMAIL IP ][7707961] cmd: MAIL FROM: <>

13:11:19.254 [MY FORTIMAIL IP ][7707961] rsp: 501 Sender address is invalid.

13:11:19.301 [MY FORTIMAIL IP ][7707961] disconnected at 05/05/2023 13:11:19

Another example:

13:12:11.623 [MY FORTIMAIL IP ][10498142] rsp: 220 mail.CUSTOMER.it

13:12:11.623 [MY FORTIMAIL IP ][10498142] connected at 05/05/2023 13:12:11

13:12:11.623 [MY FORTIMAIL IP ][10498142] Country code: FR

13:12:11.701 [MY FORTIMAIL IP ][10498142] cmd: HELO fortimail.MYSERVER.com

13:12:11.717 [MY FORTIMAIL IP ][10498142] rsp: 250 mail.CUSTOMER.it Hello [MY FORTIMAIL IP ]

13:12:11.748 [MY FORTIMAIL IP ][10498142] cmd: MAIL FROM: <>

13:12:11.748 [MY FORTIMAIL IP ][10498142] rsp: 501 Sender address is invalid.

13:12:11.795 [MY FORTIMAIL IP ][10498142] disconnected at 05/05/2023 13:12:11

Gabriele Maoret - Head of SysAdmins at SERSIS

Currently manages 6 SmarterMail installations (1 in the cloud for SERSIS which provides services to a few hundred third-party email domains + 5 on-premise for customers who prefer to have their mail server in-house)

13 Replies

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Sébastien Riccio Replied

5/7/2023 at 9:02 PM

+1 Seems to be a bug introduced in the latest build, yes.

Sébastien Riccio System & Network Admin https://swisscenter.com

Thomas Lange Replied

5/8/2023 at 5:35 AM

We are running Sophos XG as SecurityGateway in front of our SmarterMail server, including destination-email-adress verification with our SmarterMail-server. So I am now unsure if I should install build 8524 or better wait until a custom build including a fix.

Sébastien Riccio Replied

5/8/2023 at 6:23 AM

I would suggest you hold until the issue has been reviewed by ST team. Such a bug could not only lead to issue with gateways that are doing pre-delivery recipient validation, but could also lead break other things, like delivery status notifications being refused.

We're not running yet the new SmarterMail in production so I can't check myself if it has other side effects, but if I was running 8524, I would defintely check the SMTP detailed logs for "Sender address is invalid", to make sure it's not affecting other "MAIL FROM" adrresses except the NULL from "<>".

Kind regards.

Sébastien Riccio System & Network Admin https://swisscenter.com

Kyle Kerst Replied

5/8/2023 at 6:51 AM

Employee Post

Hello! Do you have this setting enabled in Settings>Antispam>Spam Checks under the Null Sender check?

Kyle Kerst IT Coordinator SmarterTools Inc. www.smartertools.com

Gabriele Maoret - SERSIS Replied

5/8/2023 at 7:07 AM

Hi Kyle!

No, that check is FULLY disabled:

Gabriele Maoret - Head of SysAdmins at SERSIS Currently manages 6 SmarterMail installations (1 in the cloud for SERSIS which provides services to a few hundred third-party email domains + 5 on-premise for customers who prefer to have their mail server in-house)

Sébastien Riccio Replied

5/8/2023 at 7:18 AM

Hello Kyle,

I would suspect this:

Fixed: Unquoted emails with a space are not being rejected as bad formatting during SMTP.

To be the origin of the issue. But I can be wrong ofc :)

Kind regards.

Sébastien Riccio System & Network Admin https://swisscenter.com

Kyle Kerst Replied

5/8/2023 at 7:48 AM

Employee Post

Thanks to both of you! I'll be digging into this once we get tickets responded to today.

Kyle Kerst IT Coordinator SmarterTools Inc. www.smartertools.com

Ryan Burglehaus Replied

5/9/2023 at 11:27 AM

Any update on this Kyle? We have an open support ticket on this, but it's stuck with no resolution. Would love to know how SM can address this.

Thanks!

Ryan

echoDreamz Replied

5/11/2023 at 10:21 AM

We are running into this now with customers who use external anti-spam providers like Cyren.

SMTP error from remote mail server after MAIL FROM:<> SIZE=7148: 501 Sender address is invalid. DT=1s

This previously was not an issue until last weeks update.

echoDreamz Replied

5/11/2023 at 10:40 AM

Was told by Kyle that the issue has been fixed in the upcoming release :)

Gabriele Maoret - SERSIS Replied

5/11/2023 at 9:33 PM

Reading SM 8531 (latest build released yesterday) release notes I can't find if this issue is solved or not...

Kyle Kerst Replied

5/16/2023 at 4:23 PM

Employee Post Marked As Resolution

Hey Gabriele, sorry for the delay on this! The SMTP bug was corrected in 8531 and is captured under this release note here:

Fixed: Unquoted emails with a space are not being rejected during SMTP sessions for their bad formatting.

We do have some additional fixes incoming though so if you haven't already upgraded you could wait for that as well.

Kyle Kerst IT Coordinator SmarterTools Inc. www.smartertools.com

Gabriele Maoret - SERSIS Replied

5/18/2023 at 12:12 AM

I can confirm that this issue has been resolved (I used custom build 8536, not 8531 with the image and character encoding bug...)

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