On Wed, 31 Oct 2007, Rex Johnston wrote:

This has been going on for years. It's definitely a `bot, as it can cause a significant jump in traffic (and your bill).

Grr. Hmm.

This looks like what I want..

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http://www.netfilter.org/projects/patch-o-matic/pom-extra.html

Adds a TARPIT target to iptables, which captures and holds incoming TCP
connections using no local per-connection resources.  Connections are
accepted, but immediately switched to the persist state (0 byte window), in
which the remote side stops sending data and asks to continue every 60-240
seconds.  Attempts to close the connection are ignored, forcing the remote
side to time out the connection in 12-24 minutes.

This offers similar functionality to LaBrea
<http://www.hackbusters.net/LaBrea/> but doesn't require dedicated hardware
or IPs.  Any TCP port that you would normally DROP or REJECT can instead
become a tarpit.

To tarpit connections to TCP port 80 destined for the current machine:

  iptables -A INPUT -p tcp -m tcp --dport 80 -j TARPIT

To significantly slow down Code Red/Nimda-style scans of unused address
space, forward unused ip addresses to a Linux box not acting as a router
(e.g. "ip route 10.0.0.0 255.0.0.0 ip.of.linux.box" on a Cisco), enable IP
forwarding on the Linux box, and add:

  iptables -A FORWARD -p tcp -j TARPIT
  iptables -A FORWARD -j DROP
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Maybe I'll also forward all incoming tcp's ports apart from the one I'm
using for ssh to the tarpit.


John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : [EMAIL PROTECTED]
New Zealand

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