Armory
wget 
(1 rating)
GNU Wget is a free software package for retrieving files using HTTP, HTTPS and FTP, the most widely-used Internet protocols. It is a non-interactive commandline tool, so it may easily be called from scripts, cron jobs, terminals without X-Windows support, etc. GNU Wget has many features to make retrieving large ...
netcat (2 ratings)
Netcat is a featured networking utility which reads and writes data across network connections, using the TCP/IP protocol. 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 ...
Scapy (4 ratings)
Scapy is a powerful interactive packet manipulation program. It is able to forge or decode packets of a wide number of protocols, send them on the wire, capture them, match requests and replies, and much more. It can easily handle most classical tasks like scanning, tracerouting, probing, unit tests, attacks ...
Wireshark 
(13 ratings)
Wireshark is the world's foremost network protocol analyzer, and is the de facto (and often de jure) standard across many industries and educational institutions.
Kiwi CatTools (2 ratings)
Kiwi CatTools automates configuration backups and management on routers, switches and firewalls. It provides e-mail notification and compare reports highlighting config changes. Supports Telnet, SSH, TFTP and SNMP.
nmap (2 ratings)
Nmap ("Network Mapper") is a free and open source utility for network exploration or security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to ...
iperf (1 rating)
Iperf was developed by NLANR/DAST as a modern alternative for measuring maximum TCP and UDP bandwidth performance. Iperf allows the tuning of various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, datagram loss.
mturoute (1 rating)
mturoute.exe is a small command line application that uses ICMP pings of various sizes in order to determine the MTU values on the path between itself and the target system. It also includes a "traceroute" like mode where it will attempt to determine the lowest MTU between the local host ...
KNOPPIX 
(2 ratings)
KNOPPIX is a bootable Live system on CD or DVD, consisting of a representative collection of GNU/Linux software, automatic hardware detection, and support for many graphics cards, sound cards, SCSI and USB devices and other peripherals. KNOPPIX can be used as a productive Linux system for the desktop, educational CD, ...
EtherApe (1 rating)
EtherApe is a graphical network monitor for Unix modeled after etherman. Featuring link layer, IP and TCP modes, it displays network activity graphically. Hosts and links change in size with traffic. Color coded protocols display. It supports Ethernet, FDDI, Token Ring, ISDN, PPP and SLIP devices. It can filter traffic ...
hping
hping is a command-line oriented TCP/IP packet assembler/analyzer. The interface is inspired to the ping(8) unix command, but hping isn't only able to send ICMP echo requests. It supports TCP, UDP, ICMP and RAW-IP protocols, has a traceroute mode, the ability to send files between a covered channel, and many ...
SING
SING stands for 'Send ICMP Nasty Garbage'. It is a tool that sends ICMP packets fully customized from command line. Its main purpose is to replace the ping command but adding certain enhancements (Fragmentation, spoofing,...)
ethtool
ethtool is used to query and modify low-level NIC settings, like speed, duplex, and autonegotiation.
lft
LFT, short for Layer Four Traceroute, is a sort of 'traceroute' that often works much faster (than the commonly-used Van Jacobson method) and goes through many configurations of packet-filters (firewalls). More importantly, LFT implements numerous other features including AS number lookups through several reliable sources, loose source routing, netblock name ...
whob
WhoB is a likable whois client designed to provide everything a network engineer needs to know about a routed IP address by typing one line and reading one line. But even so, it's worth typing a few more lines because WhoB can do lots of other cool things for you! ...
Firewalk
Firewalk is an active reconnaissance network security tool that attempts to determine what layer 4 protocols a given IP forwarding device will pass. Firewalk works by sending out TCP or UDP packets with a TTL one greater than the targeted gateway. If the gateway allows the traffic, it will forward ...
mtr
mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool. As mtr starts, it investigates the network connection between the host mtr runs on and HOSTNAME by sending packets with purposefully low TTLs. It continues to send packets with low TTL, noting the response ...
ntop
ntop is a network traffic probe that shows the network usage, similar to what the popular top Unix command does. ntop is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform and on Win32 as well. ntop users ...
NTRadPing
NTRadPing is a useful tool for testing installations of your RADIUS servers. Through NTRadPing you can simulate authentication and accounting requests and send them to the RADIUS server making NTRadPing act as a NAS client.
WANem
WANem is a wide area network emulator. It supports various features such a bandwidth limitation, latency, packet loss, network disconnection among other wide area network characteristics.
WinMTR
A win32 with GUI version of mtr (http://www.bitwizard.nl/mtr/), not quite as full featured but handy as a free and stand-alone tool.
Advanced IP Address Calculator
Advanced IP Address Calculator is an easy-to-use IP subnet calculator that lets you calculate every aspect of your subnet configuration in a few mouse clicks! The calculator generates a color-coded bit map, breaking down the network, subnet, and host portion. It shows you the subnet host address range, the subnet ...
Advanced LAN Scanner
Advanced LAN Scanner is a small, easy-to-use, highly configurable network scanner for Win32. And it's VERY fast. Advanced LAN Scanner uses multithreading so you can scan more than 1000 elements per second! If used to scan ports, Advanced LAN Scanner can scan all 65536 ports in less than a minute! ...
Advanced Port Scanner
Advanced Port Scanner is a small, fast, robust and easy-to-use port scanner for Win32 platform. It uses a multithread technique, so on fast machines you can scan ports very fast. Also, it contains descriptions for common ports, and can perform scans on predefined port ranges.
Advanced IP Scanner
Advanced IP Scanner is a fast, robust and easy-to-use IP scanner for Windows. It easily lets you have various types of information about local network computers in a few seconds! Advanced IP Scanner gives you one-click access to many useful functions - remote shutdown and wake up, Radmin integration and ...
TheDude
This is an awesome utility for doing SNMP tracking, network usage, the works! You can underlay geographical maps to use on you WAN maps or floorplans for LAN mapping. It can track just about anything under the sun that is network connected. Best of all, it's free!
LanSweeper
Lansweeper is a powerful solution to make a complete software, hardware, computer inventory of your Windows network.
Likewise Software
Securely Integrate Linux, Unix, and Mac with Active Directory by allowing the machines to join the domain and users to authenticate with their domain credentials.
ngrep
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, ICMP, IGMP and Raw protocols across ...