recipient verification for relaying mail

[Guest]

[shiveringmonkey]

Hello everyone, this is my first post to this forum, although I have been Using EFW for years now.  I thought I'd finally contribute something...

I use Endian Firewall's SPAM filtering because I don't want to go through the hassle of setting up spamassassin, amavis, etc. manually.  I set up my filtering on my EFW, and then set the smart host, and relay mail back to my mail server that my clients connect to.  I run EFW on a 650 MHz machine with 312 Mb of RAM.  I found that most of the spam that I receive is destined to bogus users.  This really creates a cpu, memory, and disk access load on my old hardware.   To get around this, I set the following in the smtpd_recipient_restrictions section of my /etc/postfix/main.cf file:
reject_unverified_recipient,

What this does is checks the relay host for the user in it's local users database, and if it isn't there, the mail is rejected at the SMTP level BEFORE it ever hits amavis/clamav/spamd.  I found that this reduces CPU and memory utilization by about 40% on my system, and decreases my load average from about 2.5 to less than 1. 

It would be nice if this were included in the web interface, but it's a pretty easy hack to decrease server load.


Hope it helps someone,

Bear