This page lists known tones that occur on the telephone line. Tones include the ones generate by the phone company, consumer products (e.g. answering machines, faxes, etc.), dialup services, etc.

Tor implements a highly customizable control protocol which can be used to tune almost all aspects of its operation.

TLS/SSL protocols support a large number of cipher suites. A cipher suite is a collection of symmetric and asymmetric encryption algorithms used by hosts to establish a secure communication. Supported cipher suites can be classified based on encryption algorithm strength, key length, key exchange and authentication mechanisms. Some cipher suites offer better level of security than others (e.g. Several weak cipher suites were developed for export to comply with US export law). There are more than 200 known cipher suites.

nmap (Network MAPper) is a network port scanner with service version and operating system detection engines. The tool was originally developed by fyodor and published in Phrack Issue 51 in 1997. The tool is command line although a number of GUIs exist. nmap runs on a variety of platforms including Linux, *BSD, Windows, and others.

hping is a TCP/IP packet forging tool with embedded Tcl scripting functionality. Developed by antirez in 1998, it is now in its 3rd release. The tool runs on all major operatings systems including Linux, *BSD, and Windows.

Scapy is a packet forging tool using Python as its domain specific language. It was developed by Philippe Biondi n 2003

Port Scanning is the process of identifying listening ports on a target system. A Port Scanner is a tool used to identify such ports. Port Scanning reveals several attributes about the target system like running services, operating system, and running applications. Although all 65,535 can be scanned, it is often more time efficient to concentrate on a subset of entire port range which includes particularly interesting services such as http and ftp servers, remote shell ports, and others. Over the time a large number of port scanning approaches was developed ranging from classic TCP connect approach to more stealthy SYN, ACK and many others. Such approaches are covered below:

This section covers various approaches to discovery of network connected hosts.