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Hping2 : A network probing utility like ping on steroids

This handy little utility assembles and sends custom ICMP, UDP, or TCP packets and then displays any replies. It was inspired by the ping command, but offers far more control over the probes sent. It also has a handy traceroute mode and supports IP fragmentation. This tool is particularly useful when trying to traceroute/ping/probe hosts behind a firewall that blocks attempts using the standard utilities. This often allows you to map out firewall rulesets. It is also great for learning more about TCP/IP and experimenting with IP protocols.

Scapy : Interactive packet manipulation tool
Scapy is a powerful interactive packet manipulation tool, packet generator, network scanner, network discovery tool, and packet sniffer. It provides classes to interactively create packets or sets of packets, manipulate them, send them over the wire, sniff other packets from the wire, match answers and replies, and more. Interaction is provided by the Python interpreter, so Python programming structures can be used (such as variables, loops, and functions). Report modules are possible and easy to make.

Nemesis : Packet injection simplified
The Nemesis Project is designed to be a commandline-based, portable human IP stack for UNIX/Linux (and now Windows!). The suite is broken down by protocol, and should allow for useful scripting of injected packet streams from simple shell scripts.

Yersinia : A multi-protocol low-level attack tool
Yersinia is a low-level protocol attack tool useful for penetration testing. It is capable of many diverse attacks over multiple protocols, such as becoming the root role in the Spanning Tree (Spanning Tree Protocol), creating virtual CDP (Cisco Discovery Protocol) neighbors, becoming the active router in a HSRP (Hot Standby Router Protocol) scenario, faking DHCP replies, and other low-level attacks.

Ntop : A network traffic usage monitor
Ntop shows network usage in a way similar to what top does for processes. In interactive mode, it displays the network status on the user’s terminal. In Web mode, it acts as a Web server, creating an HTML dump of the network status. It sports a NetFlow/sFlow emitter/collector, an HTTP-based client interface for creating ntop-centric monitoring applications, and RRD for persistently storing traffic statistics.

Ngrep : Convenient packet matching & display
ngrep strives to provide most of GNU grep’s common features, applying them to the network layer. ngrep is a pcap-aware tool that will allow you to specify extended regular or hexadecimal expressions to match against data payloads of packets. It currently recognizes TCP, UDP and ICMP across Ethernet, PPP, SLIP, FDDI, Token Ring and null interfaces, and understands bpf filter logic in the same fashion as more common packet sniffing tools, such as tcpdump and snoop.

EtherApe : EtherApe is a graphical network monitor for Unix modeled after etherman
Featuring link layer, IP and TCP modes, EtherApe displays network activity graphically with a color coded protocols display. Hosts and links change in size with traffic. It supports Ethernet, FDDI, Token Ring, ISDN, PPP and SLIP devices. It can filter traffic to be shown, and can read traffic from a file as well as live from the network.

SolarWinds : A plethora of network discovery/monitoring/attack tools
SolarWinds has created and sells dozens of special-purpose tools targeted at systems administrators. Security-related tools include many network discovery scanners, an SNMP brute-force cracker, router password decryption, a TCP connection reset program, one of the fastest and easiest router config download/upload applications available and more.

Nagios : An open source host, service and network monitoring program
Nagios is a system and network monitoring application. It watches hosts and services that you specify, alerting you when things go bad and when they get better. Some of its many features include monitoring of network services (smtp, pop3, http, nntp, ping, etc.), monitoring of host resources (processor load, disk usage, etc.), and contact notifications when service or host problems occur and get resolved (via email, pager, or user-defined method).

Argus : A generic IP network transaction auditing tool
Argus is a fixed-model Real Time Flow Monitor designed to track and report on the status and performance of all network transactions seen in a data network traffic stream. Argus provides a common data format for reporting flow metrics such as connectivity, capacity, demand, loss, delay, and jitter on a per transaction basis. The record format that Argus uses is flexible and extensible, supporting generic flow identifiers and metrics, as well as application/protocol specific information.

Netcat : The network Swiss army knife

This simple utility reads and writes data across TCP or UDP network connections. It is designed to be a reliable back-end tool that can be used directly or easily driven by other programs and scripts. At the same time, it is a feature-rich network debugging and exploration tool, since it can create almost any kind of connection you would need, including port binding to accept incoming connections. The original Netcat was released by Hobbit in 1995, but it hasn’t been maintained despite its immense popularity. It can sometimes even be hard to find nc110.tgz.

The flexibility and usefulness of this tool have prompted people to write numerous other Netcat implementations – often with modern features not found in the original. One of the most interesting is Socat, which extends Netcat to support many other socket types, SSL encryption, SOCKS proxies, and more. It even made this list on its own merits. There is also Chris Gibson’s Ncat, which offers even more features while remaining portable and compact. Other takes on Netcat include OpenBSD’s nc, Cryptcat, Netcat6, PNetcat, SBD, and so-called GNU Netcat.

Socat : A relay for bidirectional data transfer
A utility similar to the venerable Netcat that works over a number of protocols and through a files, pipes, devices (terminal or modem, etc.), sockets (Unix, IP4, IP6 – raw, UDP, TCP), a client for SOCKS4, proxy CONNECT, or SSL, etc. It provides forking, logging, and dumping, different modes for interprocess communication, and many more options. It can be used, for example, as a TCP relay (one-shot or daemon), as a daemon-based socksifier, as a shell interface to Unix sockets, as an IP6 relay, for redirecting TCP-oriented programs to a serial line, or to establish a relatively secure environment (su and chroot) for running client or server shell scripts with network connections.

Angry IP Scanner : A fast windows IP scanner and port scanner

Angry IP Scanner can perform basic host discovery and port scans on Windows. Its binary file size is very small compared to other scanners and other pieces of information about the target hosts can be extended with a few plugins.

Superscan : A Windows-only port scanner, pinger, and resolver
SuperScan is a free Windows-only closed-source TCP/UDP port scanner by Foundstone. It includes a variety of additional networking tools such as ping, traceroute, http head, and whois.

Unicornscan : Not your mother’s port scanner
Unicornscan is an attempt at a User-land Distributed TCP/IP stack for information gathering and correlation. It is intended to provide a researcher a superior interface for introducing a stimulus into and measuring a response from a TCP/IP enabled device or network. Some of its features include asynchronous stateless TCP scanning with all variations of TCP flags, asynchronous stateless TCP banner grabbing, and active/passive remote OS, application, and component identification by analyzing responses. it isn’t for the faint of heart.

Scanrand : An unusually fast stateless network service and topology discovery system
Scanrand is a stateless host-discovery and port-scanner similar in design to Unicornscan. It trades off reliability for amazingly fast speeds and uses cryptographic techniques to prevent attackers from manipulating scan results. This utility is a part of a software package called Paketto Keiretsu which was written by Dan Kaminsky.

Netfilter : The current Linux kernel packet filter/firewall

Netfilter is a powerful packet filter implemented in the standard Linux kernel. The userspace iptables tool is used for configuration. It now supports packet filtering (stateless or stateful), all kinds of network address and port translation (NAT/NAPT), and multiple API layers for 3rd party extensions. It includes many different modules for handling unruly protocols such as FTP. For other UNIX platforms (OpenBSD specific), or IP Filter. Many personal firewalls are available for Windows (Tiny,Zone Alarm, Norton, Kerio, …), though none made this list. Microsoft included a very basic firewall in Windows XP SP2, and will nag you incessantly until you install it.

Openbsd PF : The OpenBSD Packet Filter
Like Netfilter and IP Filter on other platforms, OpenBSD users love PF, their firewall tool. It handles network address translation, normalizing TCP/IP traffic, providing bandwidth control, and packet prioritization. It also offers some eccentric features, such as passive OS detection. Coming from the same guys who created OpenBSD, you can trust that it has been well audited and coded to avoid the sort of security holes we have seen in other packet filters.

IP Filter : Portable UNIX Packet Filter
IP Filter is a software package that can be used to provide network address translation (NAT) or firewall services. It can either be used as a loadable kernel module or incorporated into your UNIX kernel; use as a loadable kernel module where possible is highly recommended. Scripts are provided to install and patch system files, as required. IP Filter is distributed with FreeBSD, NetBSD, and Solaris.

Firewalk : Advanced traceroute

Firewalk employs traceroute-like techniques to analyze IP packet responses to determine gateway ACL filters and map networks. This classic tool was rewritten from scratch in October 2002. Note that much or all of this functionality can also be performed by the Hping2 –traceroute option.

Tcptraceroute : A traceroute implementation using TCP packets
The problem is that with the widespread use of firewalls on the modern Internet, many of the packets that the conventional traceroute(8) sends out (ICMP echo or UDP) end up being filtered, making it impossible to completely trace the path to the destination. However, in many cases, these firewalls will permit inbound TCP packets to specific ports that hosts sitting behind the firewall are listening for connections on. By sending out TCP SYN packets instead of UDP or ICMP ECHO packets, tcptraceroute is able to bypass the most common firewall filters.

What is Port Scanner ?

A port scanner is a piece of software designed to search a network host for open ports. This is often used by administrators to check the security of their networks and by hackers to compromise it.
Understand and Write a Port Scanner in PERL

Port scanner script in PERL

#!/usr/bin/perl

use IO::Socket;

$port = 1;

$output = “/home/sakuramboo/perl/OpenPorts.txt”;

open (LIST, ” >>$output”);

while ($port <= 65535){

$sock = new IO::Socket::INET (PeerAddr => ’127.0.0.1′,

PeerPort => $port,

Proto => ‘tcp’);

if ($sock){

close $sock;

print “$port -open\n”;

print LIST “$port -open\n”;

$port = $port + 1;

}

else{

print “$port -closed\n”;;

$port = $port + 1;

}

}

close(LIST);
now, lets take a look at how all of this works, shall we?

#!/usr/bin/perl

start off the perl script with this line.

use IO::Socket;
you are saying that you are going to be using the perl modules named IO::Socket. This allows you to utilize the commands for socket programming.

$port = 1;
you are declaring $port to equal 1.

$output = “/home/sakuramboo/perl/OpenPorts.txt”;
you are declaring that $output will be a file, and it is given then exact location of the file and file name.

open (LIST, ” >>$output”);
this opens the file from $output to allow the script to write to it.

while ($port <= 65535){
while $port (which is 1 at the start) is less than or equal to 65535 (the total number of ports a computer can have) if will do what is in the brackets.

$sock = new IO::Socket::INET
this declares that $sock will be a new socket connection.

(PeerAddr => ’127.0.0.1′,PeerPort => $port, Proto => ‘tcp’);
this is the details of $sock. PeerAddr points to the IP address you want to scan. For this script, i used the localhost. PeerPort points to $port (which starts at 1). this will be increasing as the script is run. Proto points to the protocol that is being used. If you wanted to scan ports with udp, you could. Just replace ‘tcp’ with ‘udp’.

if ($sock){
this is where the script uses the socket and attempts to make a connection with what you have in $sock. It is basically saying, “if $sock makes a connection to the settings in $sock do what is in the brackets.”

close $sock;
this closes the connection.

print “$port -open\n”;
this will print what port just got scanned and tell you that it is open, as well as return a line so everything doesnt get printed right next to each other.

print LIST “$port -open\n”;
this will print the same things that it did in the command prompt, into the file in $output.

$port = $port + 1;
this is where $port gets increased by 1.

else{

print “$port -closed\n”;

$port = $port + 1;

}
here is what happens if the port is closed. Does the same as if it was open exept that it doesnt print it to a file. I did this just so i know where it is in the port scan.

close(LIST);