1, NESSUS
http://www.nessus.org
2, Netcat
http://www.l0pht.com/~weld/netcat/
3, TCPDUMP
http://www.tcpdump.org
4, SNORT
http://www.snort.org
5, Saint
http://www.wwdsi.com/saint/
6, Ethereal
http://ethereal.zing.org/
7, WHINKER
http://www.wiretrip.net/rfp/p/doc.asp?id=21&iface=2
8, Internet Security Scanner
http://www.iss.net
9, ABACUS PortSentry
http://www.psionic.com/abacus/portSentry/
10, DSNIFF
http://naugh.monkey.org/~ DUGSONG/DSNIFF
11, TripWire
http://www.tripwire.com/
12, Cybercop
http://www.pgp.com/asp_set/products/tns/ccscanner_intro.asp
13, HPING2
http://www.kyuzz.org/antirez/hping/
14, SARA
http://www-arc.com/sara/
15, Sniffit
http://reptile.rug.ac.be/~coder/sniffit/sniffit.html
16, Satan
Http://www.fish.com/satan/
17, ipfilter
http://coombs.anu.edu.au/ipfilter
18, iptables / netfilter / ipchains / ipfwadm
http://netfilter.kernelnotes.org/
19, firewalk
http://www.packetfactory.net/projects/firewalk/
20, Strobe
http://www.insecure.org/nmap/index.html#other
21, L0PHT CRACK
http://www.l0pht.com/l0phtcrack/
22, John THE RIPPER
http://www.openwall.com/john/
23, Hunt
http://www.cri.cz/kra/index.html#hunt
24, OpenSSH / SSH
http://www.openssh.com/
http://www.ssh.com/commerce/index.html
25, TCP Wrappers
ftp://ftp.porcupine.org/pub/security/index.html
26, NTOP
http://www.ntop.org
27, Traceroute / Ping / Telnet
http://www.linux.com
28, Nat (NetBIOS Auditing Tool)
http://www.tux.org/pub/security/secnet/toLS/nat10/
29, scanlogd
http://www.openwall.com/scanlogd/
30, SAM SPADE
http://samspade.org/t/t
http://www.samspade.org/
31, NFR
http://www.nfr.com
32, Logcheck
http://www.psionic.com/abacus/logcheck/
33, Perl
http://www.perl.org
34, NGREP
Http://www.packetfactory.net/projects/ngrep/35, cheops
http://www.marko.net/cheops/
36, VeteScan
http://www.self-evident.com/
37, Retina
http://www.eeye.com/html/products/retina.html
38, LIBNET
http://www.packetfactory.net/libnet/
39, CRACK / LIBCRACK
http://www.users.dircon.co.uk/~crypto/
40, CERBERUS Internet Scanner
http://www.cerberus-infosec.co.uk/cis.shtml
41, Swatch
http://www.stanford.edu/~atkins/swatch/
42, OpenBSD
http://www.openbsd.org
43, Nemesis
http://www.packetninja.net/nemesis/
44, LSOF
ftp://vic.cc.purdue.edu/pub/tools/unix/lsof/
45, LIDS
http://www.turbolinux.com.cn/lids/
46, IPTRAF
http://cebu.mozcom.com/riker/iptraf/
47, iPlog
http://ojnk.sourceforge.net/
48, Fragrouter
http://www.anzen.com/research/nidsbench/
49, QUESO
http://www.apostols.org/projectz/queso/
50, GPG / PGP
http://www.gnupg.org/
http://www.pgp.com
