I've got an old p3, 800mhz 1u server with 128mb ram running tarpit with two external IP's (one low and one high). This way up/down, down/up scans all get hung. It answers on most external ports. One thing though, you need to tell it to ignore the broadcast. When I take the firewall and bring it back up we have seen some problems (when it starts it's arp advertisements). I've also played with mirring SMTP and HTTP but tarpit'ing seems to work the best. Has been working fine for some time... -----Original Message----- From: netfilter-bounces@xxxxxxxxxxxxxxxxxxx [mailto:netfilter-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jozsef Kadlecsik Sent: Thursday, April 21, 2005 11:50 PM To: Taylor Grant Cc: Vic N; netfilter@xxxxxxxxxxxxxxxxxxx Subject: Re: ddos / no connection tracking / tarpitting On Fri, 22 Apr 2005, Taylor Grant wrote: > > So my question is, is this the basic element of building a good > > anti-ddos solution wtih iptables to address a *large* volume of ddos > > traffic to build iptables w/o connection tracking? > > Yes this is possible and (I think) fairly easy to do. As I have never done this I can not tell you for sure, but this is what I would do if I were to do such a thing. > > I will presume that you are wanting to drop all traffic to a specif port on an IP address for the sake of this discussion. > > iptables -t raw -A PREROUTING -d 1.2.3.4 -p tcp --dport 5678 -j NOTRACK > iptables -t filter -A FORWARD -d 1.2.3.4 -p tcp --dport 5678 -j TARPIT > > This will cause any traffic that comes in that is distend to 1.2.3.4 on port 5678 to NOT be tracked with the connecting tracking sub system and to subsequently be redirected to the TARPIT target. You *must* use the rule iptables -t raw -A PREROUTING -s 1.2.3.4 -p tcp --sport 5678 -j NOTRACK as well, otherwise conntrack will pick up the reply packets from the TARPIT target. Best regards, Jozsef - E-mail : kadlec@xxxxxxxxxxxxxxxxx, kadlec@xxxxxxxxxxxxxxx PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt Address : KFKI Research Institute for Particle and Nuclear Physics H-1525 Budapest 114, POB. 49, Hungary
