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CHARGEN
The Character Generator Protocol (CHARGEN) is a service of the Internet Protocol Suite defined in in 1983 by Jon Postel. It is intended for testing, debugging, and measurement purposes. The protocol is rarely used, as its design flaws allow ready misuse. A host may connect to a server that supports the Character Generator Protocol on either Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) port number 19. Upon opening a TCP connection, the server starts sending arbitrary characters to the connecting host and continues until the host closes the connection. In the UDP implementation of the protocol, the server sends a UDP datagram containing a random number (between 0 and 512) of characters every time it receives a datagram from the connecting host. Any data received by the server is discarded. Inetd implementation On most Unix-like operating systems, a CHARGEN server is built into the inetd or xinetd daemon. The CHARGEN service is usually not enabled by defaul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barber Pole
A barber's pole is a type of sign used by barbers to signify the place or shop where they perform their craft. The trade sign is, by a tradition dating back to the Middle Ages, a staff or pole with a helix of colored stripes (often red and white in many countries, but usually red, white and blue in the United States). The pole may be stationary or may rotate, often with the aid of an electric motor. A "barber's pole" with a helical stripe is a familiar sight, and is used as a secondary metaphor to describe objects in many other contexts. For example, if the shaft or tower of a lighthouse has been painted with a helical stripe as a daymark, the lighthouse could be described as having been painted in "barber's pole" colors. Origin in barbering and surgery During medieval times, barbers performed surgery on customers, as well as tooth extractions. The original pole had a brass wash basin at the top (representing the vessel in which leeches were kept) and bottom (representi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filler Text
Filler text (also placeholder text or dummy text) is text that shares some characteristics of a real written text, but is random or otherwise generated. It may be used to display a sample of fonts, generate text for testing, or to spoof an e-mail spam filter. The process of using filler text is sometimes called '' greeking,'' although the text itself may be nonsense, or largely Latin, as in Lorem ipsum. Asdf ASDF is the sequence of letters that appear on the first four keys on the home row of a QWERTY or QWERTZ keyboard. They are often used as a sample or test case or as random, meaningless nonsense. It is also a common learning tool for keyboard classes, since all four keys are located on Home row. Etaoin shrdlu "Etaoin shrdlu" is the approximate order of frequency of the twelve most commonly used letters in the English language, best known as a nonsense phrase that sometimes appeared in print in the days of "hot type" publishing due to a custom of Linotype machine operat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denial-of-service Attack
In computing, a denial-of-service attack (DoS attack) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. In a distributed denial-of-service attack (DDoS attack), the incoming traffic flooding the victim originates from many different sources. More sophisticated strategies are required to mitigate this type of attack, as simply attempting to block a single source is insufficient because there are multiple sources. A DoS or DDoS attack is analogous to a group of people crowding the entry door of a shop, making it hard for legitimate customers to enter, thus disrupting trade. Criminal perpetrators of DoS attacks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Name Server
A name server refers to the server component of the Domain Name System (DNS), one of the two principal namespaces of the Internet. The most important function of DNS servers is the translation (resolution) of human-memorable domain names (example.com) and hostnames into the corresponding numeric Internet Protocol (IP) addresses (192.0.2.1), the second principal name space of the Internet, which is used to identify and locate computer systems and resources on the Internet. Although it is typically used in reference to DNS (Domain Name System), the term name server may also be used for any computer application that implements a network service for providing responses to queries against a directory service which translates an often humanly meaningful, text-based identifier to a system-internal, often numeric identification or addressing component. This service is performed by the server in response to a service protocol request. Domain Name Server The Internet maintains two prin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Application Layer Protocols
Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a communications network * Function application, in mathematics and computer science Processes and documents * Application for employment, a form or forms that an individual seeking employment must fill out * College application, the process by which prospective students apply for entry into a college or university * Patent application, a document filed at a patent office to support the grant of a patent Other uses * Application (virtue), a characteristic encapsulated in diligence * Topical application A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Protocol
The Time Protocol is a network protocol in the Internet Protocol Suite defined in 1983 in RFC 868 by Jon Postel and K. Harrenstein. Its purpose is to provide a site-independent, machine readable date and time. The Time Protocol may be implemented over the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). A host connects to a server that supports the Time Protocol on port 37. The server then sends the time as a 32-bit unsigned integer in binary format and in network byte order, representing the number of seconds since 00:00 (midnight) 1 January, 1900 GMT, and closes the connection. Operation over UDP requires the sending of any datagram to the server port, as there is no connection setup for UDP. The fixed 32-bit data format means that the timestamp rolls over approximately every 136 years, with the first such occurrence on 7 February 2036. Programs that use the Time Protocol must be carefully designed to use context-dependent information to distinguish thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daytime Protocol
The Daytime Protocol is a service in the Internet Protocol Suite, defined in 1983 in RFC 867. It is intended for testing and measurement purposes in computer networks. A host may connect to a server that supports the Daytime Protocol on either Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) port 13. The server returns an ASCII character string of the current date and time in an unspecified format. Inetd implementation On UNIX-like operating systems a daytime server is usually built into the inetd (or xinetd) daemon. The service is usually not enabled by default. It may be enabled by adding the following lines to the file {{mono, /etc/inetd.conf and telling inetd to reload its configuration: daytime stream tcp nowait root internal daytime dgram udp wait root internal An example output may be: Thursday, February 2, 2006 13:45:51-PST See also * List of well-known ports * Echo Protocol * QOTD * Time Protocol The Time Protocol is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QOTD
The Quote of the Day (QOTD) service is a member of the Internet protocol suite, defined in RFC 865. As indicated there, the QOTD concept predated the specification, when QOTD was used by mainframe sysadmins to broadcast a daily quote on request by a user. It was then formally codified both for prior purposes as well as for testing and measurement purposes. A host may connect to a server that supports the QOTD protocol, on either TCP or UDP port 17. To keep the quotes at a reasonable length, RFC 865 specifies a maximum of 512 octets for the quote. Although some sources indicate that the QOTD service is rarely enabled, and is in any case often firewalled to avoid denial-of-service attacks, interest continues in the pre-existing purpose of serving quotes as can be seen with web engine searches. Current testing and measurement of IP networks is more commonly done with ping and traceroute, which are more robust adaptations of the echo protocol The Echo Protocol is a service in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discard Protocol
The Discard Protocol is a service in the Internet Protocol Suite defined in RFC 863. It was designed for testing, debugging, measurement, and host-management purposes. A host may send data to a host that supports the Discard Protocol on either Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) port number 9. The data sent to the server is simply discarded. No response is returned. For this reason, UDP is usually used, but TCP allows the services to be accessible on session-oriented connections (for example via HTTP proxies or some virtual private network (VPN)). Inetd implementation On most Unix-like operating systems a discard server is built into the inetd (or xinetd) daemon. The discard service is usually not enabled by default. It may be enabled by adding the following lines to the file and reloading the configuration: discard stream tcp nowait root internal discard dgram udp wait root internal The Discard Protocol is the TCP/UD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echo Protocol
The Echo Protocol is a service in the Internet Protocol Suite defined in RFC 862. It was originally proposed for testing and measurement of round-trip times in IP networks. A host may connect to a server that supports the Echo Protocol using the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP) on the well-known port number 7. The server sends back an identical copy of the data it received. Inetd implementation On UNIX-like operating systems an echo server is built into the inetd family of daemons. The echo service is usually not enabled by default. It may be enabled by adding the following lines to the file and telling inetd to reload its configuration: echo stream tcp nowait root internal echo dgram udp wait root internal On various routers, this TCP or UDP port 7 for the Echo Protocol for relaying ICMP datagrams (or port 9 for the Discard Protocol) is also configured by default as a proxy to relay Wake-on-LAN (WOL) magic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printer (computing)
In computing, a printer is a peripheral machine which makes a persistent representation of graphics or text, usually on paper. While most output is human-readable, bar code printers are an example of an expanded use for printers. Different types of printers include 3D printers, inkjet printers, laser printers, and thermal printers. History The first computer printer designed was a mechanically driven apparatus by Charles Babbage for his difference engine in the 19th century; however, his mechanical printer design was not built until 2000. The first patented printing mechanism for applying a marking medium to a recording medium or more particularly an electrostatic inking apparatus and a method for electrostatically depositing ink on controlled areas of a receiving medium, was in 1962 by C. R. Winston, Teletype Corporation, using continuous inkjet printing. The ink was a red stamp-pad ink manufactured by Phillips Process Company of Rochester, NY under the name Clear Prin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows NT 4
Windows NT 4.0 is a major release of the Windows NT operating system developed by Microsoft and oriented towards businesses. It is the direct successor to Windows NT 3.51, which was released to manufacturing on July 31, 1996, and then to retail on August 24, 1996. It was Microsoft's primary business-oriented operating system until the introduction of Windows 2000. Workstation, server and embedded editions were sold, and all editions feature a graphical user interface similar to that of Windows 95, which was superseded by Windows 98 and could still be directly upgraded by either Windows 2000 Professional or Windows Me. Mainstream support for Windows NT 4.0 Workstation ended on June 30, 2002, following by extended support ending on June 30, 2004. Windows NT 4.0 Server mainstream support ended on December 31, 2002, with extended support ending on December 31, 2004. Windows NT 4.0 Embedded mainstream support ended on June 30, 2003, followed by extended support on July 11, 2006, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
