tcptraceroute is a traceroute implementation using TCP packets.
The more traditional traceroute(8) sends out either UDP or ICMP ECHO packets with a TTL of one, and increments the TTL until the destination has been reached. By printing the gateways that generate ICMP time exceeded messages along the way, it is able to determine the path […]

fping is a ping(1) like program which uses the Internet Control Message Protocol (ICMP) echo request to determine if a host is up. fping is different from ping in that you can specify any number of hosts on the command line, or specify a file containing the lists of hosts to ping. Instead of trying […]

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 […]

Arpwatch is the classic ARP man-in-the-middle attack detector from LBNL’s Network Research Group. It syslogs activity and reports certain changes via email. Arpwatch uses LibPcap to listen for ARP packets on a local ethernet interface.

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 […]