Discussion of emails that are always in quarantine on the PMG server

[arroby]

Hello All

Is there an issue here, some domains always enter email quarantine on proxmox, in this case where our PMG server is used as an SMTP server, the customer has the right to use this SMTP service as long as the IP of the customer connection has been allowed on the PMG Server side, here is the full header :


As additional information, in our environment we do implement a config spamscore of 5,

What we want to ask, suggestions that can be done to reduce the spam score, at this time we have tried to apply changes to the localhost rdns to our smtp server hostname, following capture header logs via our smtp server, :

We have also confirmed some email rules so that they don't enter spamming or quarantine such as setting dkim, spf, setting ptr in each IP block,

Sorry if there are questions or there are duplicate discussions on this forum, if there is, please provide the reference for the link, because we have tried to search for some literature and still haven't found the right solution.

Thank you for your attention and cooperation.

 

[Stoiko Ivanov]

Is there an issue here, some domains always enter email quarantine on proxmox, in this case where our PMG server is used as an SMTP server, the customer has the right to use this SMTP service as long as the IP of the customer connection has been allowed on the PMG Server side, here is the full header

There are quite a few markers that take this mail over the 5 points which the sending server (or user agent should fix) :
TO_EQ_FM_DIRECT_MX
TO_EQ_FM_HTML_ONLY
FSL_HELO_NON_FQDN_1
MISSING_DATE
MISSING_MID

almost all sensible SMTP servers will add a message-id and date header if it's absent
Sending from and to the same address is usually quite an odd thing to do
the mail-server should be configured to use it's fqdn (and not only the part before the first '.' when issueing the HELO/EHLO command

quick question - is this a mail-server connecting to PMG - or is your client using something like thunderbird to send mails?
if it's the latter - keep in mind that PMG is meant to be used as proxy between your mail-server and the internet and not as a mail submission server

I'd suggest you fix the issues with your client - if the mail gets detected as spam by PMG chances are high that it will get detected as spam by the receiving server as well.

I hope this helps!

 

[arroby]

There are quite a few markers that take this mail over the 5 points which the sending server (or user agent should fix) :
TO_EQ_FM_DIRECT_MX
TO_EQ_FM_HTML_ONLY
FSL_HELO_NON_FQDN_1
MISSING_DATE
MISSING_MID

almost all sensible SMTP servers will add a message-id and date header if it's absent
Sending from and to the same address is usually quite an odd thing to do
the mail-server should be configured to use it's fqdn (and not only the part before the first '.' when issueing the HELO/EHLO command

quick question - is this a mail-server connecting to PMG - or is your client using something like thunderbird to send mails?
if it's the latter - keep in mind that PMG is meant to be used as proxy between your mail-server and the internet and not as a mail submission server

I'd suggest you fix the issues with your client - if the mail gets detected as spam by PMG chances are high that it will get detected as spam by the receiving server as well.

I hope this helps!

Hi Stoiko thanks for your response,

Yes, my client used mail client like a outlook and thunderbird,

Once information, currently this server used PMG service as SMTP Relay for my client.

 

[Stoiko Ivanov]

As said and documented in the reference docs:
https://pmg.proxmox.com/pmg-docs/pmg-admin-guide.html#chapter_deployment

PMG is mostly meant to be used as proxy between an actual mail-server and the internet - not for sending mails from a mail-client

However Thunderbird and Outlook usually do not generate such broken mails? (no message-id, no date-header)?

If all else is not possible you can disable the MISSING_DATE and MISSING_MID rules:
https://pmg.proxmox.com/pmg-docs/pmg-admin-guide.html#pmgconfig_spamdetector (section 4.8.3)
and check if postfix does add these headers upon receiving.