Re: [cobalt-users] SOLVED: Sendmail 8.9.3 and ORDB

[Parker Morse <morse@xxxxxxxxxxx>]

A few keywords for the archives: DNSBL, black lists, spam blocking.

On Wednesday, March 19, 2003, at 11:48  PM, Mike's List wrote:
> On Wed, 19 Mar 2003, Bill Gunning wrote:
> > I have been following this discussion for a while, and have search
> > the archives... But I am still trying to figure-out how this works, does
> > adding these lines slow down sendmail? Also do you have to have
> > an agreement or sign-up to use relays.osirusoft.com, relays.ordb.org
> > or relays.ordb.org
> >
> > Also how long does it take sendmail to check the email?

> It'll take some CPU process from your system to compares w/the list,
> there's no agreement or such.  Since this afternoon, my mail log logged
> 23442 spams denied from njabl, 6893 spams denied from spamcop, 6084 spams
> denied from osirusoft.  DNSBL might not be 100% perfect, but close enough.
>
> Very much worth the effort to put in a few lines in your sendmail.cf.

(1) It's best to do the modifications in the sendmail.mc file (redhat.mc, 
cobalt.mc, depending on your system) as I've detailed on my page 
<http://bluebird.sinauer.com/~morse/cobalt/>. Mike worked directly on the 
.cf file because, for various reasons, he didn't have an .mc file to start 
with.

(2) Yes, there's a CPU/time hit. It's less than that of processing all the 
spam, so IMHO it's worth it, and I don't get anywhere near the volume Mike 
does.

(3) I followed Dan's suggestion a few months ago and started sending 
bounces to a page on my site explaining our email policy, rather than 
sending them directly to the DNSBL home page. I find I get a lot more 
understanding in the event of mistakes, that way. Our page is at 
<http://www.sinauer.com/contact/email.php> and gives links for one-click 
queries of the lists; I'd be happy to share the PHP code off-list (it's 
very simple) or consider anyone's suggestions.

(4) The MAPS RBL charges for site-wide use. bl.spamcop.net would 
appreciate your donations. The others vary, they're mostly free 
("Relays.osirusoft.com not only does not request, but refuses any 
financial contributions." - from their front page) but some will accept 
donations of cash or assistance in serving the zone.

Disclaimer: Please at least be aware of all the issues when you start 
using a DNSBL! I've got a brief outline of them on my page. I find them 
very helpful and effective, but I'm not running your server, nor am I 
providing email service to paying customers. If they work for you, great, 
but they're not for everyone.

pjm