A long time ago, I used a program that would insert itself between the server mailbox and my local client software and I could "bounce" spam emails back so they appeared to the sender that my email address didn't exist. I thought I heard about it here.

Does anyone happen to remember what that is called and if that trick even works?

My spam is now getting close to 40 spams/day. I'm blocking their domains on my server-side mailbox, but still new ones appear everyday and are getting through.

You mean like greylisting?

http://en.wikipedia.org/wiki/Greylisting

I'm not sure if that's what you're talking about. My work uses greylisting to control spam. It sends an email back to the sender, and most legitimate servers will try to send the email again. Once the second email comes in, our server knows it is from a legit source and lets it through. In theory, spam servers don't try again.

I haven't heard of greylisting before, but no, that's not what I'm talking about.

This software sends a fake email back to the sender that appears to be from my email server. The difference is that I pick and choose which emails to do that to, where greylisting seems to be a blanket approach.

I had the idea of doing something like that but I figured someone else already did it. I was right I guess.

Greylisting doesn't send an e-mail back, it rejects the e-mail with a temporary error.

And I doubt that bouncing spam will have much effect because spammers simply won't read any answer they get. And if they do than it's probably because you bounced the mail back to some poor guy whose adress they faked.

This. Don't bounce emails back for this reason. All you're doing is adding to the spam. If you can't configure the server to drop the email or return with a permanent error, then just send it to your junk mail. Most spammers don't even check to see if email is valid or not anyway. They either know it's valid already (from a spam list) or they're just carpet bombing.

This is correct. About 6 months ago I installed a computer here at work between the router and the switch. It runs Linux as the OS and a free software package called Untangle. Works great for us against spam, especially the pesky self-spam (from-spoofing). It also contains a lot of other really nice features such as web filtering, spam blocker, phishing blocker, virus blocker, intrusion prevention, and more. What makes this nice is that all of this is being handled by this box before it ever touches the servers. It also supports a DMZ configuration, for those that are interested. I highly recommend it.

[url]www.untangle.com[/url]

I use GMail and 99% of spam goes directly into the spam folder, whilst all the mail I want to read appears in the inbox. Because of this, I have no problem with spam on gmail. I don't understand why people are bothered by spam that collects in the spam folder, when you never have to look at it if you don't want to.