[Techtalk] block spam

[Pierre Fortin]

On Fri, 17 May 2002 kansas_kennedy at phreaker.net wrote:

> I'm using k-mail and getting spam from a particular domain for about two 
> months now. I tried to filter _any header_  equals email address with filter 
> action >> bounce and apply filter on incoming messages. But kmail could not 
> be able to do anything....& after setting this filter I received two more 
> mails from that domain.
> 
> Now, I want to block anything and everything from that particular domain 
> coming to my machine through K-mail and instead, if possible, bouce that mail 
> back to the root at thatdomain with the full header.
> 
> Anyone knows how can I do this?

If you're running postfix, I started documenting this at 
http://pfortin.com/Linux/PostFix/  If not, you are at the mercy of your 
ISP or whoever runs your mailhost.

If you run any mailer (postfix, sendmail,...) and the sender is one or 
a few IP addresses, you can just go "dark" on the net by adding an 
iptables filter...  here's a simple script I use for this:

/root/bin/drop:
  #!/bin/sh
  IP=$1
  PORT=$2
  iptables -A INPUT -s $IP -p tcp --dport $PORT -j DROP

& call it with:  bin/drop IP_addr 25

I *HATE* spam and my setup pretty blocks all but the odd message every 
week or two...

HTH,
Pierre