1 Topic by Ange7 (edited by Ange7 2024-01-16 18:26:39)

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Topic: No notification when email is rejected

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.6.8
- Deployed with iRedMail Easy or the downloadable installer? downloadable installer
- Linux/BSD distribution name and version: debian 11.8
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MariaDB
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hello,

Sometime i have this in my logs mail :

Jan 15 16:01:06 mx postfix/postscreen[1255152]: CONNECT from [217.70.183.201]:42575 to [my.server.ip]:25
Jan 15 16:01:12 mx postfix/postscreen[1255152]: PASS NEW [217.70.183.201]:42575
Jan 15 16:01:12 mx postfix/smtpd[1255155]: connect from relay8-d.mail.gandi.net[217.70.183.201]
Jan 15 16:01:12 mx postfix/smtpd[1255155]: discarding EHLO keywords: CHUNKING
Jan 15 16:01:12 mx postfix/smtpd[1255155]: Anonymous TLS connection established from relay8-d.mail.gandi.net[217.70.183.201]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Jan 15 16:01:12 mx postfix/smtpd[1255155]: discarding EHLO keywords: CHUNKING
Jan 15 16:01:12 mx postfix/smtpd[1255155]: lost connection after EHLO from relay8-d.mail.gandi.net[217.70.183.201]
Jan 15 16:01:12 mx postfix/smtpd[1255155]: disconnect from relay8-d.mail.gandi.net[217.70.183.201] ehlo=2 starttls=1 commands=3

And i don't receive any mail (i have same problem with ipv6)

How to debug / fix this ?

thank you

----

Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2 Reply by Ange7 (edited by Ange7 2024-01-16 00:02:47)

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Re: No notification when email is rejected

Ok i found :

it was the size limit of message was too low (i fixed with https://www.sysarchitects.com/solved-po … hlo-rhel7)

but it's not normal to delete mail without any notification...

Can we get one mail on postmaster@ (for example) for mail locked ? Or maybe send one bounce to the sender that to inform him that his mail will be never read...

Thank you

3 Reply by Pavel Zhe (edited by Pavel Zhe 2024-01-16 01:34:49)

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Re: No notification when email is rejected

Ange7 wrote:

Sometime i have this in my logs mail :

Jan 15 16:01:12 mx postfix/smtpd[1255155]: discarding EHLO keywords: CHUNKING

And i don't receive any mail (i have same problem with ipv6)

How to debug / fix this ?

thank you

'discarding EHLO keywords: CHUNKING' is mean that postfix was configured to resist newly discovered 'SMTP Smuggling attack'. iRedmail 1.6.8 was released for this.

4 Reply by Ange7

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Re: No notification when email is rejected

The real problem was someone sent me one mail with attachment with size greater than the size limit and nothing in log or bounce…

5 Reply by Cthulhu

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Re: No notification when email is rejected

If size limit is reached, server rejects the mail, doesn't send a bounce

6 Reply by Ange7

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Re: No notification when email is rejected

Cthulhu wrote:

If size limit is reached, server rejects the mail, doesn't send a bounce

it's not normal to reject mail without any notification anywhere

7 Reply by Pavel Zhe (edited by Pavel Zhe 2024-01-17 00:30:43)

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Re: No notification when email is rejected

Ange7 wrote:
Cthulhu wrote:

If size limit is reached, server rejects the mail, doesn't send a bounce

it's not normal to reject mail without any notification anywhere

Mail can be REJECTED with code 5XX (e.g., 550 - No such user), or TEMPORARILY REJECTED with 4xx (e.g., 471 -Greylisting in progress). If session closed after EHLO stage, it mean that message transfer was never started - no MAIL FROM, no RCPT TO, and no DATA stages

If you worry about message size - check /var/log/maillog for something look like

(message size 5414717 exceeds size limit 5242880 of server
127.0.0.1[127.0.0.1])

8 Reply by Ange7

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Re: No notification when email is rejected

Pavel Zhe wrote:
Ange7 wrote:
Cthulhu wrote:

If size limit is reached, server rejects the mail, doesn't send a bounce

it's not normal to reject mail without any notification anywhere

Mail can be REJECTED with code 5XX (e.g., 550 - No such user), or TEMPORARILY REJECTED with 4xx (e.g., 471 -Greylisting in progress). If session closed after EHLO stage, it mean that message transfer was never started - no MAIL FROM, no RCPT TO, and no DATA stages

If you worry about message size - check /var/log/maillog for something look like

(message size 5414717 exceeds size limit 5242880 of server
127.0.0.1[127.0.0.1])

Nothing like this in log

But after I changed size limit, the mail was correctly delivered.

It’s why I said it’s not normal that one mail was rejected without any informations.

Only logs I posted here.

9 Reply by ZhangHuangbin

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Re: No notification when email is rejected

Ange7 wrote:

It’s why I said it’s not normal that one mail was rejected without any informations.

What if spammers send you a lot spams and your server rejects them all?

10 Reply by Ange7 (edited by Ange7 2024-01-22 23:24:36)

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Re: No notification when email is rejected

ZhangHuangbin wrote:
Ange7 wrote:

It’s why I said it’s not normal that one mail was rejected without any informations.

What if spammers send you a lot spams and your server rejects them all?

A summary on postmaster@ with :

xxx@xxxx.com : reject 6 times
yyy@yyyy.com : reject 1 time
zzz@zzzz.com : reject 2 times

Maybe with the reason ?

11 Reply by ZhangHuangbin

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Re: No notification when email is rejected

Ange7 wrote:
ZhangHuangbin wrote:
Ange7 wrote:

It’s why I said it’s not normal that one mail was rejected without any informations.

What if spammers send you a lot spams and your server rejects them all?

A summary on postmaster@ with :

xxx@xxxx.com : reject 6 times
yyy@yyyy.com : reject 1 time
zzz@zzzz.com : reject 2 times

Maybe with the reason ?

You can run "logwatch" to get such summary, including reject reasons.