Re: Wrong timestamp added by sendmail in Received: header?

Hi!

Am 24.03.25 um 15:54 schrieb Matus UHLAR - fantomas:
> On 24.03.25 15:19, Andreas Haumer wrote:
>> Recently I noticed a (at least for me) very strange problem
>> with a mailserver running sendmail + SpamAssassin: sometimes
>> (not always!) the Received: header inserted by sendmail is completely wrong,
>> triggering SpamAssassin rules like "T_DATE_IN_FUTURE_96_Q"
>>
>> More details: this is an internet-facing mail MX, currently running Debian 10
>> with sendmail 8.15.2 and spamass-milter 0.4.0
> 
> note that with milter, current Received: header is NOT the one produced by MTA but by spamass-milter. The milter protocol provides message exactly as it came without local additions like Received: header.
> 
> This also means that Received: header spamd sees as mail is being received is diferent than the one you see later.
> 
> looking at logs I've had similar problem years ago:
> 
> https://marc.info/?l=spamassassin-users&m=139282758624769&w=2
> without success:
> https://marc.info/?l=spamassassin-users&m=139410750008972&w=2
> 
> 
> and IIRC the working solution was to avoid sending 'b' macro at all, so spamass-milter generates its own.
> 
> 

Thank you!
This was very important input!

I now also found this on the Debian bug tracker: "spamass-milter adds bad Received: header, creating false positive"
<https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=775183>

As well as this: "confMILTER_MACROS_ENVRCPT should probably not contain {b} macro"
<https://github.com/andybalholm/spamass-milter/issues/9>

It seems I've hit a very old bug!

I have now changed my milter configuration to:

INPUT_MAIL_FILTER(`opendkim', `S=local:/var/run/opendkim/opendkim.sock')
INPUT_MAIL_FILTER(`pyspf-milter', `S=local:/run/pyspf-milter/pyspf-milter.sock')dnl
INPUT_MAIL_FILTER(`opendmarc', `S=local:/var/run/opendmarc/opendmarc.sock')dnl
INPUT_MAIL_FILTER(`spamassassin', `S=local:/var/run/spamass/spamass.sock, F=, T=C:15m;S:4m;R:4m;E:10m')dnl

define(`confMILTER_MACROS_CONNECT',`t, b, j, _, {daemon_name}, {if_name}, {if_addr}')dnl
define(`confMILTER_MACROS_HELO',`s, {tls_version}, {cipher}, {cipher_bits}, {cert_subject}, {cert_issuer}')dnl
define(`confMILTER_MACROS_ENVFROM',`{auth_authen}')dnl
define(`confMILTER_MACROS_ENVRCPT',`i, j, r, v, Z, {auth_type}')dnl

I now have the "b" macro in MILTER_MACROS_CONNECT only
(as suggested by the debian bugreport)

Now I have to wait and see if that helps.
(Of course I restarted sendmail now so I have to look very carefully
if the inserted "Received" header now contains the correct timestamp.

Regards,

- andreas

-- 
Andreas Haumer
*x Software + Systeme              | mailto:[email protected]
Karmarschgasse 51/2/20             | https://www.xss.co.at/
A-1100 Vienna, Austria             | Tel: +43-1-6060114

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