[KLUG Members] using sendmail to block spam

[Adam Bultman]

On Fri, 10 Jan 2003, bill wrote:

> Can anybody comment on the following description:
> 
> http://www.sdsc.edu/~jeff/spam/Sendmail.html
> 
> Is the patch legit?  If so, how would it be applied?


>From what I saw, it's not really a patch, just info to add to your MC file 
that is just a bunch of rbl blacklists. 

I have the ordb.org one in my MC file, and I don't know if I've rejected 
mail yet (although I use(d) it at home before, and saw them get rejected).

You edit your .mc file (assumed to be in your sendmail source tree) and 
add it, then build it with:

./Build install-cf  

in the same dir as the .mc directory (assuming sendmail.mc file name).

this will be in:

sendmail-<rev>/cf/cf/

There are some bare .mc files in there already.  I'd recommend hitting: 
http://www.sendmail.org/tips/relaying.html
and
http://www.sendmail.org/compiling.html

For building it.  There are pages on the net that have all possible .mc 
lines, which is useful if you are doing a lot with it.


If you want an example .mc file, write me back, and I'll send you mine.  
I'd highly recommend making sure you aren't a open relay, too - you don't 
want to be on the other end of the blacklist, you know ;)

Cyrus SASL can be used for smtp auth, and there are simple .mc additions 
you can add (i.e. relay_hosts_only) to make sure you have to specifically 
add ips/domains before they can send through you.

To test if you are an open relay, you can go to www.ordb.org and have them 
test you. However, the down side, if they find you are an open relay - you 
are on the rbl, and have to fix yourself before you'll be removed.

HTH

Adam


> 
> Then, there's that cryptic lines:
> 
> "Add these rules to the end of your .mc file, build a new .cf file with it,
> install, and restart sendmail to make all of the changes take effect."
> 
> Adding to the end of .mc sounds o.k., but how to build a new .cf file with it?
> 
> Install?  Install what?
> 
> Restarting sendmail sounds do-able.
> 
> Any other comments on this?
> 
> kind regards,
> 
> bill hollett
> 
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