Nolisting

[tminchin_ironport]

Here's an interesting way to reduce spam:

http://www.joreybump.com/code/howto/nolisting.html

Setting your primary MX to be something which does not accept email.

I've also noticed that setting your firewall or IPS to reject packets which exceed their advertised MSS reduces connections too.

[Donald Nash]

There's a good /. discussion about it at <>.

Personally, I'm skeptical. Just because it worked for him doesn't mean it's a general solution. Many people have experienced exactly the opposite behavior from spammers: they try the lower priority MX records first, or they ignore the MX priorities entirely.

I put this in the same category as many other so-called "solutions" to the spam problem. They're temporary hacks which will only work so long as they don't gain critical mass, otherwise spammers will adapt. And once spammers quit exhibiting the particular behaviors these tactics target, these tactics will fail completely because they have no ability to adapt to new spamming behavior. Contrast this with, for example, robust content filters such as Brightmail and IronPort Anti-Spam, which are able to adapt as spammers change their content tactics.

Anyway, just my opinion.

[Erich_ironport]

I agree completely, it is a kludge at best.

Another one that annoys me is the idea of using a long delay before responding to the EHLO or before giving the banner, and dropping client that jump the gun and respond before the banner or the EHLO response.

It's a pain to debug a SMTP problem when you have to wait 30 seconds or more for a hello banner to respond after to connection is open. It's just another so called "solution" to stopping spammers.

In my opinion SMTP CallBacks fall into this group of spam kludges also.

Erich