Derchris at 16:23, 5 April 2010

Derchris — Mon, 05 Apr 2010 16:23:19 GMT

← Older revision		Revision as of 16:23, 5 April 2010
Line 12:		Line 12:

	;; ANSWER SECTION:		;; ANSWER SECTION:
-	dk._domainkey.<domain>. 3600 IN TXT "k=rsa\; t=y\; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDq4XiKzLKI/biXkAHM3smiSnsJ1FOLjlTrrH1CJfh0SOnBjR1YcNfCWnGyQFLdyUbdGj4AMEJIr8/jZszDgSLTFDYxPh2Yl0BDcfXhldLXq1yAJYB8k4JYOwoDINnXV26asjtfEH0NH0v9ue/lifc69zuGuJ2j3VFqBPD1+03QSwIDAQAB"	+	dk._domainkey.<domain>. 3600 IN TXT "k=rsa\; t=y\; p=Long RSA key"
	</pre>}}		</pre>}}

Derchris: / derchris / - Added dk-filter setup Page

Derchris — Mon, 05 Apr 2010 16:22:25 GMT

*/ derchris */ - Added dk-filter setup Page

New page

=Check DNS settings=

First check that Domainkeys is setup ok in DNS

{{cmd|<pre>
#dig _domainkey.<domain> TXT

;; ANSWER SECTION:
_domainkey.<domain>. 3600 IN TXT "t=y\; o=-"

#dig dk._domainkey.<domain> TXT

;; ANSWER SECTION:
dk._domainkey.<domain>. 3600 IN TXT "k=rsa\; t=y\; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDq4XiKzLKI/biXkAHM3smiSnsJ1FOLjlTrrH1CJfh0SOnBjR1YcNfCWnGyQFLdyUbdGj4AMEJIr8/jZszDgSLTFDYxPh2Yl0BDcfXhldLXq1yAJYB8k4JYOwoDINnXV26asjtfEH0NH0v9ue/lifc69zuGuJ2j3VFqBPD1+03QSwIDAQAB"
</pre>}}

In this example, I created a _domainkey DNS TXT entry with "t=y; o=-", and a Selector dk._domainkey with "k=rsa t=y p=<RSA Key>"
The RSA key is the same as for DKIM, which is already setup via Amavis

=Install dk-filter=

Install dk-filter

{{cmd|<pre>
#apt-get install dk-filter
</pre>}}

=Check dk-filter user/group=

Check if dk-filter user/group has been added

{{cmd|<pre>
#grep dk-filter /etc/passwd
dk-filter:x:125:132::/var/run/dk-filter:/bin/false

#grep dk-filter /etc/group
dk-filter:x:132:
</pre>}}

If not, create the user/group, with /var/run/dk-filter as home dir.

=Configure dk-filter=

Open /etc/default/dk-filter:
{{cfg|/etc/default/dk-filter |<pre>
# Sane defaults: log to syslog
DAEMON_OPTS="-l"
DAEMON_OPTS="$DAEMON_OPTS -b s -c simple -d <domain> -D -h -m ORIGINATING -s /var/lib/dkim/<domain>.pem -S <selector>"
SOCKET="inet:4445@127.0.0.1"
</pre>}}

dk-filter will sign mails on 127.0.0.1:4445 for Domain <domain>, with keys from /var/lib/dkim/<domain>.pem using Selector <selector>
You need to change this to your environment (domain, selector)

=Configure postfix=

Open /etc/postfix/master.conf, and go down to the Amavis smtpd
{{cfg|/etc/postfix/master.conf |<pre>
127.0.0.1:10025 inet n - - - - smtpd
-o content_filter=
-o milter_default_action=accept
-o milter_macro_daemon_name=ORIGINATING
-o smtpd_milters=inet:127.0.0.1:4445 # Add this to the Postfix config
-o local_recipient_maps=
-o relay_recipient_maps=
-o smtpd_restriction_classes=
-o smtpd_delay_reject=no
-o smtpd_client_restrictions=permit_mynetworks,reject
-o smtpd_helo_restrictions=
-o smtpd_sender_restrictions=
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o mynetworks_style=host
-o mynetworks=127.0.0.0/8
-o strict_rfc821_envelopes=yes
-o smtpd_error_sleep_time=0
-o smtpd_soft_error_limit=1001
-o smtpd_hard_error_limit=1000
-o smtpd_client_connection_count_limit=0
-o smtpd_client_connection_rate_limit=0
-o receive_override_options=no_header_body_checks,no_unknown_recipient_checks,no_address_mappings
</pre>}}

=Start dk-filter=

Start dk-filter, and then restart Postfix
{{cmd|<pre>
#/etc/init.d/dk-filter start
</pre>}}

Check if dk-filter is running

Then restart Postfix
{{cmd|<pre>
#/etc/init.d/postfix restart
</pre>}}

=Test Domainkeys=

Domainkeys should now be working.
In order to test it, send a blank email to:

check-auth@verifier.port25.com

Wait for the reply. It should show like this

<pre>
==========================================================
Summary of Results
==========================================================
SPF check: pass
DomainKeys check: pass
DKIM check: pass
Sender-ID check: pass
SpamAssassin check: ham
</pre>

Addition/Configure dk-filter to sign emails with Domainkeys - Revision history

Derchris at 16:23, 5 April 2010

Derchris: */ derchris */ - Added dk-filter setup Page

Derchris: / derchris / - Added dk-filter setup Page