Howdy all,
I thought I'd pass on my experiences with some other spam fighting tools.
I recently took over a system administration position with an implementation of dspam in place. I am spectacularly unimpressed with dspam. It is a resource nightmare, and, contrary to its advertised statistics, it has a surprisingly high error ratio. dspam stores all of its data in a database. In our implementation, that is PostgreSQL. When dspam was writing to Postgres it would literally stop even the console from responding. And this is a 2.25 GHz dual Xenon machine with 2 GBs of ram! Dspam stores so much crap to the database that I had to move the entire database to a ram disk to avoid disk thrashing our RAID5.
To be fair, our RAID5 setup left a lot to be desired. It was on 3 125GB IDE disks on a 3Ware card, and that is a truly awful configuration. I've since converted it to RAID1 (2 drives mirrored and 1 left for hot-swap) and that helped a bunch with the system slowdown.
So, scratch dspam.
What has been amazingly effective, both at work and here, is to setup greylisting.
http://greylisting.org http://projects.puremagic.com/greylisting
OpenBSD (my OS of choice) has an implementation of greylisting in the default install, and it was simply a matter of turning it on and inserting a couple of rules into the firewall configuration to make it work.
The result has been dramatic. Legitimate e-mail is slowed only marginally the first time mail is received from a specific mail server. Spam, though, is another story.
The truth is in the numbers. At openvistas.net, I was already rejecting mail for non-existent users before it hit qmail thanks to the qmail patches at
http://www.fehcom.de/qmail/spamcontrol.html
Even so, I was running almost 6000 messages in my personal pending queue over a 14 day period. Multiply that over the 100+ users I supply e-mail to...no wonder I always had nearly 300 messages in the qmail-queue--almost all from [EMAIL PROTECTED] going to non-existent spammers.
I turned on spamd early Thursday morning. All of Friday I had 5 spams added to my pending queue. So far today I've added another 7. Since this is new territory to me, I've been watching like a hawk to make sure I'm not losing legitimate mail. I'm not. The qmail queue is at 218 and falling as those old messages hit the 7 day limit and are dropped.
tmda still has a role in my battle against spam. At this point in time, even 7 spams a day would be intolerable, but it appears I've just learned how to lessen its load considerably.
Jeff
-- Jeff Ross Open Vistas Networking, Inc. http://www.openvistas.net _____________________________________________ tmda-users mailing list ([EMAIL PROTECTED]) http://tmda.net/lists/listinfo/tmda-users
