Setting up rblsmtpd

March 16, 2017 by Roberto Puzzanghera 4 comments

NB: you can skip this page if you decided to use qmail-dnsbl instead


A Realtime Block List (RBL) is a list of addresses that an RBL list supplier believes are a source of Spam.
rblsmtpd blocks mail from RBL-listed sites. It works with any SMTP server that can run under tcpserver.

qmail-smtpd's run script is already set to run rblsmtpd before qmail-smtpd. The following lines are related to rblsmtpd (others are omitted):

# This enables greetdelay anti-spam functionality on rblsmtpd
export GREETDELAY=15

# This disables rblsmtpd reject
#export RBLSMTPD=""

exec /usr/local/bin/softlimit -m "$SOFTLIMIT" \
    /usr/local/bin/tcpserver -v -H -R -l 0 \
    -x /home/vpopmail/etc/tcp.smtp.cdb -c "$MAXSMTPD" \
    -u "$QMAILDUID" -g "$NOFILESGID" 0 25 \
    /usr/local/bin/rblsmtpd -W \
        -b -r \
        -b -r \
    /var/qmail/bin/qmail-smtpd 2>&1

Since rblsmtpd is the first program who talks with the sender you may want to enable the GREETDELAY here and not inside qmail-smtpd. GREETDELAY=15 sets a delay of 15 seconds. In this example two different RBL sources will be queried. If their responce is ok the qmail-smtpd program will be run.

To disable rblsmtpd you have to delete the following lines from the code above:

/usr/local/bin/rblsmtpd -W \
        -b -r \
        -b -r \

NB: If you decide to use as suggested here, check the free use terms and be aware that exceeding these terms causes the cut off of your server. I think that one of my servers has been banned, since I can't resolve


Connect to Russel Nelson's site and follow the instructions. In a few words you have to do a telnet from your mail server and look if is working fine as a filter.

Howto avoid being "cut off" by

You may be interested at this point to take a look to the idea of Costel Balta, which is addressed to decrease the amount of connections to the RBL lists, avoiding to be banned consequently.




This text is awesome!

I have only one question

Is there any place where i can change the annoying rblsmtpd.local? that's the text appearing in SMTP GREETING 220 rblsmtpd.local.

Thanks in advance

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you have to modify rblsmtpd.c

you have to modify rblsmtpd.c at line 201/203 and recompile. It should be quite easy to build a patch that reads the control/me file and use its contents as the rblsmtpd helo..

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Thanks Man! I did it and it

Thanks Man! I did it and it works great!

I made some modifications in order to use other Antivirus and the speed of the services is awesome.

Thanks again!

Reply |

Receiving lots of spam mail

Hi Enetcs and All,

We have qmail server version [qmail-toaster-1.03-1.3.22] installed. This installation and configuration has been made by some one else/x colleague.

We are dealing problem of receiving spam mail.  In /var/qmail/contrl/blacklist file having only one entry i.e. -r Spamassian version is spamassassin-toaster-3.3.2-1.4.3.

Can you guide me how to stop or atleast decrease the frequency of receiving spam mail?

Thanks in advance.

Reply |