There may be a slight amount of confusion here and I can understand why. Google use DKIM whereas Yahoo and AOL use DomainKeys. They can both use the same DNS record (in fact I do use the same DNS record for both) and the same key for signing, but the actual signature is different.

I just noticed this article is worded incorrectly, this article is for DomainKeys but not actually for DKIM.

Also. if Google believes you’re bulk mailing I would take a much closer look at your mail logs and make sure that you’re only relaying for your other domains, and not acting as an open relay to the world.

Hope that helps a little.

Kura

Walter Schreppers:

Hi,
Got it working a few hours later, still thanks for the reply. It seems the only thing that went wrong was _domainkey.sitweb.eu had not propegated yet As it started working the next day without me doing anything else .
Now for the bad news, google is still bouncing my mails. Hotmail, yahoo and latinmail.com etc all accept my mails since I started using dkim with dk-filter daemon.
This is the kind of error I get in mail.log :
to=, orig_to=, relay=gmail-smtp-in.l.google.com[74.125.39.27]:25, delay=32, delays=0.09/0.01/0.14/32, dsn=5.7.1, status=bounced (host gmail-smtp-in.l.google.com[74.125.39.27] said: 550-5.7.1 [85.10.204.201 1] Our system has detected an unusual rate of 550-5.7.1 unsolicited mail originating from your IP address. To protect our 550-5.7.1 users from spam, mail sent from your IP address has been blocked. 550-5.7.1 Please visit http://www.google.com/mail/help/bulk_mail.html to review 550 5.7.1 our Bulk Email Senders Guidelines. y8si8435401faj.183 (in reply to end of DATA command))
So I’ve got a number of domains running on this server it is not sending spam but it is relaying mails (virtual in postfix). So for example walter@schreppers.com and walter@sitweb.eu get relayed to schreppers@gmail.com. These above (and other mail adresses) do receive some spam and this is the reason gmail has started to bounce if I use sentmail from this host.
What would be a workaround for this situation?
The strange thing is when I send something from hotmail.com to walter@schreppers.com it arrives without problems so luckily that keeps on working it’s just sending from the server itself which is blocked due to spam arriving on these mails.
Anyway maybe you have a good solution for this (there seem to be a lot of people complaining about that google 550 error but haven’t seen any answers on this).
Thanks in advance should you find the time to answer.
Kind regards,
Walter

Got it working a few hours later, still thanks for the reply. It seems the only thing that went wrong was _domainkey.sitweb.eu had not propegated yet As it started working the next day without me doing anything else .

Now for the bad news, google is still bouncing my mails. Hotmail, yahoo and latinmail.com etc all accept my mails since I started using dkim with dk-filter daemon.

This is the kind of error I get in mail.log :
to=, orig_to=, relay=gmail-smtp-in.l.google.com[74.125.39.27]:25, delay=32, delays=0.09/0.01/0.14/32, dsn=5.7.1, status=bounced (host gmail-smtp-in.l.google.com[74.125.39.27] said: 550-5.7.1 [85.10.204.201 1] Our system has detected an unusual rate of 550-5.7.1 unsolicited mail originating from your IP address. To protect our 550-5.7.1 users from spam, mail sent from your IP address has been blocked. 550-5.7.1 Please visit http://www.google.com/mail/help/bulk_mail.html to review 550 5.7.1 our Bulk Email Senders Guidelines. y8si8435401faj.183 (in reply to end of DATA command))

So I’ve got a number of domains running on this server it is not sending spam but it is relaying mails (virtual in postfix). So for example walter@schreppers.com and walter@sitweb.eu get relayed to schreppers@gmail.com. These above (and other mail adresses) do receive some spam and this is the reason gmail has started to bounce if I use sentmail from this host.

What would be a workaround for this situation?
The strange thing is when I send something from hotmail.com to walter@schreppers.com it arrives without problems so luckily that keeps on working it’s just sending from the server itself which is blocked due to spam arriving on these mails.

Anyway maybe you have a good solution for this (there seem to be a lot of people complaining about that google 550 error but haven’t seen any answers on this).

Thanks in advance should you find the time to answer.

Kind regards,
Walter

What do you see if you run: sudo netstat -utanp | grep 12345

Does netstat show you that the socket is being used by your dk-filter process?

Are you using any kind of firewall? Sadly the only one I am familiar with is iptables, if you’re using iptables then running “sudo iptables -L” will show you your currently employed ruleset, you need to check to make sure you’re not doing anything to the “lo” interface that could be blocking dk-filter access.

The other possibility is that Postfix is running in a very restrictive chroot environment, if you installed via APT or using an official Debian/Ubuntu package this shouldn’t be an issue though.

Walter Schreppers:

Thanks for this great tutorial. I’m trying to set this up to be able to send to gmail again.
All seems to work (I’ve setup mail._domainkey.sitweb.eu) and can check it is working with dig.
Except I get this error in my mail.log:
warning: connect to Milter service inet:localhost:12345: Connection refused
Do I need to do something to open port 12345 on debian? Maybe my iptables is blocking it. Or otherwise how to check the dk-filter daemon is running ok?
host01:/etc/default# ps -ef | grep dk
109 16745 1 0 01:28 ? 00:00:00 /usr/bin/dk-filter -u dk-filter -P /var/run/dk-filter/dk-filter.pid -p /var/run/dk-filter/dk-filter.sock -l
root 18558 15770 0 02:21 pts/0 00:00:00 grep dk
host01:/etc/default# cat /var/run/dk-filter/dk-filter.pid
16745
host01:/etc/default# cat /var/run/dk-filter/dk-filter.sock
cat: /var/run/dk-filter/dk-filter.sock: No such device or address
host01:/etc/default#
I verify it is not working when using telnet here:
host01:/etc/default# cat /etc/default/dk-filter
# Sane defaults: log to syslog
#DAEMON_OPTS=”-l”
# Sign for domain.tld with key in /etc/mail/domainkey.key using
# selector ’2007′ (e.g. 2007._domainkey.domain.tld)
#DAEMON_OPTS=”$DAEMON_OPTS -d sitweb.eu -s /etc/postfix/dk.key -S mail”
DAEMON_OPTS=”-l -d sitweb.eu -s /etc/postfix/dk.key -S mail”
# See dk-filter(8) for a complete list of options
#
# Uncomment to specify an alternate socket
#SOCKET=”/var/run/dk-filter/dk-filter.sock” # default
#SOCKET=”inet:54321″ # listen on all interfaces on port 54321
#SOCKET=”inet:8892@localhost” # listen on loopback on port 8892
SOCKET=”inet:12345@localhost” # listen on loopback on port 12345
host01:/etc/default# telnet localhost 12345
Trying 127.0.0.1…
telnet: Unable to connect to remote host: Connection refused
host01:/etc/default#
Only change I made is putting the the key in /etc/postfix/dk.key (since I did not have a mail dir).
Any thoughts on how to resolve my issue?

All seems to work (I’ve setup mail._domainkey.sitweb.eu) and can check it is working with dig.

Except I get this error in my mail.log:
warning: connect to Milter service inet:localhost:12345: Connection refused

Do I need to do something to open port 12345 on debian? Maybe my iptables is blocking it. Or otherwise how to check the dk-filter daemon is running ok?

host01:/etc/default# ps -ef | grep dk
109 16745 1 0 01:28 ? 00:00:00 /usr/bin/dk-filter -u dk-filter -P /var/run/dk-filter/dk-filter.pid -p /var/run/dk-filter/dk-filter.sock -l
root 18558 15770 0 02:21 pts/0 00:00:00 grep dk
host01:/etc/default# cat /var/run/dk-filter/dk-filter.pid
16745
host01:/etc/default# cat /var/run/dk-filter/dk-filter.sock
cat: /var/run/dk-filter/dk-filter.sock: No such device or address
host01:/etc/default#

I verify it is not working when using telnet here:
host01:/etc/default# cat /etc/default/dk-filter
# Sane defaults: log to syslog
#DAEMON_OPTS=”-l”
# Sign for domain.tld with key in /etc/mail/domainkey.key using
# selector ’2007′ (e.g. 2007._domainkey.domain.tld)
#DAEMON_OPTS=”$DAEMON_OPTS -d sitweb.eu -s /etc/postfix/dk.key -S mail”

DAEMON_OPTS=”-l -d sitweb.eu -s /etc/postfix/dk.key -S mail”

# See dk-filter(8) for a complete list of options
#
# Uncomment to specify an alternate socket
#SOCKET=”/var/run/dk-filter/dk-filter.sock” # default
#SOCKET=”inet:54321″ # listen on all interfaces on port 54321
#SOCKET=”inet:8892@localhost” # listen on loopback on port 8892
SOCKET=”inet:12345@localhost” # listen on loopback on port 12345

host01:/etc/default# telnet localhost 12345
Trying 127.0.0.1…
telnet: Unable to connect to remote host: Connection refused
host01:/etc/default#

Only change I made is putting the the key in /etc/postfix/dk.key (since I did not have a mail dir).

Any thoughts on how to resolve my issue?