Uberspace U7 mail filter

Outdated This article is marked outdated. Also, I moved to mailbox.org.

With the upcoming uberspace 7 the guys at uberspace introduced a new environment with various changes in comparison to u6 (see u7 changelog).

One major aspect is the deprecation of dpsam and spamassassin (which I just managed to setup flawlessly :). However, with U7.1 spam is now handled globally via rspamd.

The following post will show a server-side mail filter that sorts spam, newsletters and service-emails into dedicated folders.

Once spam is detected, the header X-Rspamd-Bar, X-Rspamd-Report and X-Rspamd-Score are attached to the mail. X-Rspamd-Bar contains an spam-indicator based on - and +, e.g. the value +++ indicates quite certainly spam an e-mail flagged with -- might contain some useful contents.

Due to the huge amount of daily spam e-emails it's sensible to perform a server-side sorting via mailfilter as described in the old uberspace wiki.

A good starting point for a modulized mailfilter can be found in macfrogs blog, 2014.

When it comes to actually filter the e-mails, following rules came in handy:

# Here go the filter rules...
# Move all mails with a bar greater `+++` to .Junk
if ( /^X-Rspamd-Bar:\s\+\+\+[+]/:h ) {
    DESTDIR="$MAILDIR/.Junk" }
# Sort newsletters
elsif ( /^List-ID:.*/:h ) {
    DESTDIR="$MAILDIR/.newsletters" }
# Sort e-mails provided by services (e.g. twitter/tumblr).
elsif ( /^Delivered-To:.*-*@.*$/:h )
  {
    DESTDIR="$MAILDIR/.services"
 }

A clutched version of the whole script (based on uberspacece and macfrog) looks like this and needs to be placed in the file ~/.mailfilter:

mailfilter.sh (Source)

	`# which maildir is to use?`

	`# set default Maildir`
	`MAILDIR="$HOME/Maildir"`

	`# check if we're called from a .qmail-EXT instead of .qmail`
	`import EXT`
	`if ( $EXT )`
	`{`
	`# does a vmailmgr user named $EXT exist?`
	`# if yes, deliver mail to his Maildir instead`
	CHECKMAILDIR = `dumpvuser $EXT \| grep '^Directory' \| awk '{ print $2 }'`
	`if ( $CHECKMAILDIR )`
	`{`
	`MAILDIR="$HOME/$CHECKMAILDIR"`
	`}`
	`}`


	`# move spam to .Junk folder`
	`DESTDIR="$MAILDIR"`

	`# Here go the filter rules...`

	`if ( /^X-Rspamd-Bar:\s\+\+\+[+]/:h )`
	`{`
	`DESTDIR="$MAILDIR/.Junk"`
	`}`
	`elsif ( /^List-ID:.*/:h )`
	`{`
	`DESTDIR="$MAILDIR/.newsletters"`
	`}`
	`elsif ( /^Delivered-To:.-@.*$/:h )`
	`{`
	`DESTDIR="$MAILDIR/.services"`
	`}`


	`# Hierarchically create DESTDIR if it does not already exist.`
	`HIER="$DESTDIR"`
	`CONTINUE=1`
	`while ( $CONTINUE && $HIER =~ /^(.\/(\.[^.]+))(\.[^.]+)$/ )`
	`{`
	`if ( $MATCH3 ne ".INBOX" )`
	`{`
	`test -d "$MATCH"`
	`if ( $RETURNCODE == 1 )`
	`{`
	`maildirmake "$MATCH"`
	`}`
	`else`
	`{`
	`CONTINUE=0`
	`}`
	`}`
	`HIER=$MATCH1`
	`}`

	`# Deliver mail. If SILENT_DESTDIR is set, mark all mail in`
	`# DESTDIR as read.`
	`if ( $SILENT_DESTDIR )`
	`{`
	`# mark as read`
	`cc "$DESTDIR"`
	`find "$DESTDIR/new/" -mindepth 1 -maxdepth 1 -type f -printf '%f\0' \| xargs -0 -I {} mv "$DESTDIR/new/{}" "$DESTDIR/cur/{}:2,S"`
	`exit`
	`}`
	`else`
	`{`
	`to "$DESTDIR"`
	`}`

The stored mailfilter can be activated via account by editing the corresponding .qmail-* file and setting its content to |maildrop.

As always, more verbose configurations with various, differing mailfilters via user, are feasible.

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