On Thu, Feb 10, 2022 at 01:50:36PM -0600, Edward Sandberg wrote:
> I am attempting to configure content filtering by following this guide:
>
> http://www.postfix.org/FILTER_README.html
>
> I have added the filter service and modified the smtp service in master.cf:
>
> filter unix - n n - 10 pipe
> flags=Rq user=filter null_sender=
> argv=/home/filter/filter.sh -f ${sender} -- ${recipient}
> smtp inet n - y - - smtpd
> -o content_filter=filter:dummy
This enables content-filtering of email that arrives from *outside*
via SMTP!
> smtp unix - - y - - smtp
> -o content_filter=filter:dummy
This has no effect
> relay unix - - y - - smtp
> -o syslog_name=postfix/$service_name
> -o content_filter=filter:dummy
Nor this. Delivery agents don't run content filters, which
are assigned on input to preëmpt normal transport resolution.
> echo "body of your email" |
> mail -s "This is a subject too" \
> -a "From:redac...@redacted.com" redac...@redacted.com
>
> This is the syslog outout I see:
>
> Feb 10 19:39:03 postfix postfix/pickup[13850]: 7D1D0E0E6F: uid=0
> from=<redac...@redacted.com>
> Feb 10 19:39:03 postfix postfix/cleanup[13903]: 7D1D0E0E6F:
> message-id=<20220210193903.7d1d0e0...@postfix.redacted.net>
> Feb 10 19:39:03 postfix postfix/qmgr[13849]: 7D1D0E0E6F:
> from=<redac...@redacted.com>, size=393, nrcpt=1 (queue active)
> Feb 10 19:39:04 postfix postfix/smtp[13905]: 7D1D0E0E6F:
> to=<redac...@redacted.com>, relay=ASPMX.L.GOOGLE.com[173.194.219.26]:25,
> delay=0.61, delays=0.03/0.03/0.24/0.31, dsn=2.0.0, status=sent (250
> 2.0.0 OK 1644521944 i1si9676536ybt.537 - gsmtp)
> Feb 10 19:39:04 postfix postfix/qmgr[13849]: 7D1D0E0E6F: removed
>
> What am I missing?
The message was injected locally via sendmail -> postdrop -> pickup(8),
not via SMTP, so was not subjected to SMTP input specific filter
settings.
--
Viktor.
