DNS BlackLists

Richard Siddall richard.siddall at ELIRION.NET
Fri Jun 7 21:32:15 IST 2002

"Henry C. Chorlian" wrote:
> Were do you put this configuration in sendmail?  I'm running
> sendmail8.12.3


You don't ;>

Kelly posted a snippet from sendmail.cf.  Editing sendmail.cf was so error-prone
that sendmail went to generating the sendmail.cf from a sendmail.mc file using a
macro processing program called m4.

Unless there's a good reason to hand-edit your sendmail.cf, make a backup copy of
your sendmail.mc file and insert something like the following:
FEATURE(dnsbl,`relays.ordb.org',`Mail from $&{client_addr} rejected - see http://ordb.org/')dnl
for each of the blacklists you wish to use.
Then rebuild your sendmail.cf file.

(Actually, I'd recommend checking you can generate a sendmail.cf from your original
sendmail.mc before making any changes.)

WARNING: The name and parameters of the feature may have changed from the version
of sendmail I'm using and the one you are.

You're telling m4 to use the DNSBL macro, which expands to code to check a DNS
blacklist.  The first parameter is the DNS server to check, the second the
(hopefully useful) error message to send when you reject a message.

I think this is a sendmail FAQ.  Have a look at the sendmail site.


        Richard Siddall.

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