Hi Anton, > Dear all, > > Is it possible to detect and/or disable nmap SYN scan with ipfw? > I've added rule follow below, it catchs some packets from nmap but not all > > deny tcp from any to me dst-port 22,25,53,80,443 \ > tcpflags syn,!fin,!ack,!psh,!rst,!urg\ > tcpoptions mss,window,!sack,ts,!cc
nmap SYN scan don't use TCP options at all IIRC. MSS and TS are very common these days, so I guess you could drop TCP SYN packets which don't have one of those. Be warned nevertheless that some older systems might not be able to establish a connection anymore. I think the correct way to do this is indeed using an IDS. Regards, -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org > _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw To unsubscribe, send any mail to "[EMAIL PROTECTED]"
