Proxmox Mail Gateway can check the DKIM signature of the sender

[othmane el kheiar]

Hi,

I have a question about DKIM signature.

when a message is coming to proxmox mail gateway , it can check the DKIM signature of the sender ?

is enabled by default or i have some steps to enable DKIM verification of sender in Proxmox Mail Gateway.


my version : Mail Gateway 7.2-1

Thank you.

 

[Stoiko Ivanov]

when a message is coming to proxmox mail gateway , it can check the DKIM signature of the sender ?

There are SpamAssassin rules, which check the signature and assign points based on if it exists and is valid.

You can adjust their score if you wish to quarantine mails with invalid signature:
section 4.8.3 in https://pmg.proxmox.com/pmg-docs/pmg-admin-guide.html#pmgconfig_spamdetector

I hope this helps!

 

[othmane el kheiar]

How to enable SpamAssassin to verify DKIM signature of the sender?.

I found no information in the link you sent me.

https://pmg.proxmox.com/pmg-docs/pmg-admin-guide.html#pmgconfig_spamdetector

I am using Mail Gateway version 7.2-1.

Please can you help me ?

 

[Stoiko Ivanov]

check the logs of such a mail - pmg-smtp-filter will print which spamassassin rules hit - and there are rules which trigger on DKIM

 

[othmane el kheiar]

I have an example of an email received from offresonline@offresonline.com.





Mar 13 10:36:32 pmg postfix/smtpd[174470]: connect from tbjjbihbhfcci.turbo-smtp.net[199.187.175.228]
Mar 13 10:36:33 pmg postfix/smtpd[174470]: BC728E1115: client=tbjjbihbhfcci.turbo-smtp.net[199.187.175.228]
Mar 13 10:36:34 pmg postfix/cleanup[174479]: BC728E1115: message-id=<64-0124d6b5-0000183cc9641e012001-001-398c8029@serversmtpbond.com>
Mar 13 10:36:34 pmg postfix/qmgr[37966]: BC728E1115: from=<offresonline@offresonline.com>, size=7665, nrcpt=1 (queue active)
Mar 13 10:36:34 pmg pmg-smtp-filter[145269]: E1122640EEEA246086: new mail message-id=<64-0124d6b5-0000183cc9641e012001-001-398c8029@serversmtpbond.com>#012
Mar 13 10:36:34 pmg postfix/smtpd[174470]: disconnect from tbjjbihbhfcci.turbo-smtp.net[199.187.175.228] ehlo=1 mail=1 rcpt=1 data=1 quit=1 commands=5
Mar 13 10:36:37 pmg pmg-smtp-filter[145269]: E1122640EEEA246086: SA score=0/5 time=2.925 bayes=undefined autolearn=ham autolearn_force=no hits=AWL(0.533),DKIM_SIGNED(0.1),DKIM_VALID(-0.1),DKIM_VALID_AU(-0.1),DKIM_VALID_EF(-0.1),HTML_MESSAGE(0.001),HTML_TAG_BALANCE_BODY(0.1),MIME_HTML_ONLY(0.1),RCVD_IN_DNSWL_HI(-5),SPF_HELO_NONE(0.001),SPF_PASS(-0.001),URIBL_BLOCKED(0.001)
Mar 13 10:36:37 pmg postfix/smtpd[174505]: connect from localhost.localdomain[127.0.0.1]
Mar 13 10:36:37 pmg postfix/smtpd[174505]: 5C6ACE112A: client=localhost.localdomain[127.0.0.1], orig_client=tbjjbihbhfcci.turbo-smtp.net[199.187.175.228]
Mar 13 10:36:37 pmg postfix/cleanup[174476]: 5C6ACE112A: message-id=<64-0124d6b5-0000183cc9641e012001-001-398c8029@serversmtpbond.com>
Mar 13 10:36:37 pmg postfix/qmgr[37966]: 5C6ACE112A: from=<offresonline@offresonline.com>, size=8995, nrcpt=1 (queue active)
Mar 13 10:36:37 pmg pmg-smtp-filter[145269]: E1122640EEEA246086: accept mail to <info@attime-technologies.com> (5C6ACE112A) (rule: default-accept)
Mar 13 10:36:37 pmg postfix/smtpd[174505]: disconnect from localhost.localdomain[127.0.0.1] ehlo=1 xforward=1 mail=1 rcpt=1 data=1 commands=5
Mar 13 10:36:37 pmg pmg-smtp-filter[145269]: E1122640EEEA246086: processing time: 3.142 seconds (2.925, 0.078, 0)
Mar 13 10:36:37 pmg postfix/lmtp[174481]: BC728E1115: to=<info@attime-technologies.com>, relay=127.0.0.1[127.0.0.1]:10024, delay=4.3, delays=1/0.03/0.05/3.2, dsn=2.5.0, status=sent (250 2.5.0 OK (E1122640EEEA246086))
Mar 13 10:36:37 pmg postfix/qmgr[37966]: BC728E1115: removed
Mar 13 10:36:37 pmg postfix/smtp[174507]: 5C6ACE112A: to=<info@attime-technologies.com>, relay=192.168.11.101[192.168.11.101]:25, delay=0.27, delays=0.05/0.03/0/0.19, dsn=2.6.0, status=sent (250 2.6.0 <64-0124d6b5-0000183cc9641e012001-001-398c8029@serversmtpbond.com> [InternalId=2632814952449, Hostname=EX-SRV.offresonline.net] 10331 bytes in 0.108, 92,889 KB/sec Queued mail for delivery)
Mar 13 10:36:37 pmg postfix/qmgr[37966]: 5C6ACE112A: removed

 

[othmane el kheiar]

In this example can you help me to know that SpamAssassin verify DKIM signature of the sende or not?

 

[Stoiko Ivanov]

DKIM_SIGNED(0.1),DKIM_VALID(-0.1),DKIM_VALID_AU(-0.1)

this means it's present and valid...