Topic: Computing/Networking (Page 2)

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πŸ”— Warchalking

πŸ”— Computing πŸ”— Computer Security πŸ”— Computer Security/Computing πŸ”— Computing/Computer Security πŸ”— Computing/Networking

Warchalking is the drawing of symbols in public places to advertise an open Wi-Fi network. Inspired by hobo symbols, the warchalking marks were conceived by a group of friends in June 2002 and publicised by Matt Jones who designed the set of icons and produced a downloadable document containing them. Within days of Jones publishing a blog entry about warchalking, articles appeared in dozens of publications and stories appeared on several major television news programs around the world.

The word is formed by analogy to wardriving, the practice of driving around an area in a car to detect open Wi-Fi nodes. That term in turn is based on wardialing, the practice of dialing many phone numbers hoping to find a modem.

Having found a Wi-Fi node, the warchalker draws a special symbol on a nearby object, such as a wall, the pavement, or a lamp post. Those offering Wi-Fi service might also draw such a symbol to advertise the availability of their Wi-Fi location, whether commercial or personal.

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πŸ”— Intelink

πŸ”— Computing πŸ”— Computing/Networking

Intelink is a group of secure intranets used by the United States Intelligence Community. The first Intelink network was established in 1994 to take advantage of Internet technologies (though not connected to the public Internet) and services to promote intelligence dissemination and business workflow. Since then it has become an essential capability for the US intelligence community and its partners to share information, collaborate across agencies, and conduct business. Intelink refers to the web environment on protected top secret, secret, and unclassified networks. One of the key features of Intelink is Intellipedia, an online system for collaborative data sharing based on MediaWiki. Intelink uses WordPress as the basis of its blogging service.

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πŸ”— NCP, the Predecessor of TCP/IP

πŸ”— Computing πŸ”— Computing/Networking

The Network Control Program (NCP) provided the middle layers of the protocol stack running on host computers of the ARPANET, the predecessor to the modern Internet.

NCP preceded the Transmission Control Protocol (TCP) as a transport layer protocol used during the early ARPANET. NCP was a simplex protocol that utilized two port addresses, establishing two connections, for two-way communications. An odd and an even port were reserved for each application layer application or protocol. The standardization of TCP and UDP reduced the need for the use of two simplex ports for each application down to one duplex port.

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πŸ”— Sorcerer's Apprentice Syndrome

πŸ”— Computing πŸ”— Computing/Networking

Sorcerer's Apprentice Syndrome (SAS) is a network protocol flaw in the original versions of TFTP. It was named after Goethe's poem "Der Zauberlehrling" (popularized by the "Sorcerer's Apprentice" segment of the animated film Fantasia), because the details of its operation closely resemble the disaster that befalls the sorcerer's apprentice: the problem resulted in an ever-growing replication of every packet in the transfer.

The problem occurred because of a known failure mode of the internetwork which, through a mistake on the part of the TFTP protocol designers, was not taken into account when the protocol was designed; the failure mode interacted with several details of the mechanisms of TFTP to produce SAS.

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πŸ”— Wireless USB

πŸ”— Computing πŸ”— Computing/Networking

Wireless USB was a short-range, high-bandwidth wireless radio communication protocol created by the Wireless USB Promoter Group which intended to increase the availability of general USB-based technologies. It is unrelated to Wi-Fi. It was maintained by the WiMedia Alliance which ceased operations in 2009. Wireless USB is sometimes abbreviated as "WUSB", although the USB Implementers Forum discouraged this practice and instead prefers to call the technology Certified Wireless USB to distinguish it from the competing UWB standard.

Wireless USB was based on the (now defunct) WiMedia Alliance's Ultra-WideBand (UWB) common radio platform, which is capable of sending 480Β Mbit/s at distances up to 3 metres (9.8Β ft) and 110Β Mbit/s at up to 10 metres (33Β ft). It was designed to operate in the 3.1 to 10.6Β GHz frequency range, although local regulatory policies may restrict the legal operating range in some countries.

The standard is now obsolete, and no new hardware has been produced for many years.

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πŸ”— AMPRNet: Amateur Packet Radio Network

πŸ”— Computing πŸ”— Amateur radio πŸ”— Computing/Networking

The AMPRNet (AMateur Packet Radio Network) or Network 44 is used in amateur radio for packet radio and digital communications between computer networks managed by amateur radio operators. Like other amateur radio frequency allocations, an IP range was provided in 1981 for Amateur Radio Digital Communications (a generic term) and self-administered by radio amateurs. In 2001, undocumented and dual-use of 44.0.0.0/8 as an internet telescope began, recording the spread of the Code Red II worm in July 2001.

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πŸ”— Secure Remote Password protocol

πŸ”— Computing πŸ”— Computing/Networking

The Secure Remote Password protocol (SRP) is an augmented password-authenticated key agreement (PAKE) protocol, specifically designed to work around existing patents.

Like all PAKE protocols, an eavesdropper or man in the middle cannot obtain enough information to be able to brute force guess a password without further interactions with the parties for each guess. Furthermore, being an augmented PAKE protocol, the server does not store password-equivalent data. This means that an attacker who steals the server data cannot masquerade as the client unless they first perform a brute force search for the password.

In layman's terms, during SRP (or any other PAKE protocol) authentication, one party (the "client" or "user") demonstrates to another party (the "server") that they know the password, without sending the password itself nor any other information from which the password can be derived. The password never leaves the client and is unknown to the server.

Furthermore, the server also needs to know about the password (but not the password itself) in order to instigate the secure connection. This means that the server also authenticates itself to the client, without reliance on the user parsing complex URLs. This prevents Phishing.

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πŸ”— Internet 0

πŸ”— Computing πŸ”— Computing/Networking

Internet 0 is a low-speed physical layer designed to route 'IP over anything.' It was developed at MIT's Center for Bits and Atoms by Neil Gershenfeld, Raffi Krikorian, and Danny Cohen. When it was invented, a number of other proposals were being labelled as "internet 2." The name was chosen to emphasize that this was designed to be a slow, but very inexpensive internetworking system, and forestall "high-performance" comparison questions such as "how fast is it?"

Effectively, it would enable a platform for pervasive computing -- everything in a building could be on the same network to share data gathering and actuation. A light switch could turn on a light bulb by sending a packet to it, they can be linked together by the user.

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πŸ”— Domain Fronting

πŸ”— Internet πŸ”— Computing πŸ”— Computing/Computer Security πŸ”— Computing/Websites πŸ”— Computing/Networking

Domain fronting is a technique for Internet censorship circumvention that uses different domain names in different communication layers of an HTTPS connection to discreetly connect to a different target domain than is discernable to third parties monitoring the requests and connections.

Due to quirks in security certificates, the redirect systems of the content delivery networks (CDNs) used as 'domain fronts', and the protection provided by HTTPS, censors are typically unable to differentiate circumvention ("domain-fronted") traffic from overt non-fronted traffic for any given domain name. As such they are forced to either allow all traffic to the domain frontβ€”including circumvention trafficβ€”or block the domain front entirely, which may result in expensive collateral damage and has been likened to "blocking the rest of the Internet".

Domain fronting does not conform to HTTP standards that require the SNI extension and HTTP Host header to contain the same domain. Many large cloud service providers, including Amazon, Microsoft, and Google, actively prohibit domain fronting, which has limited it as a censorship bypass technique. Pressure from censors in Russia and China is thought to have contributed to these prohibitions, but domain fronting can also be used maliciously.

A newer variant of domain fronting, domain hiding, passes an encrypted request for one resource (say, a website), concealed behind an unencrypted (plaintext) request for another resource whose DNS records are stored in the same cloud. It has much the same effect. Refraction networking is an application of the broader principle.

πŸ”— Nagle's Algorithm

πŸ”— Internet πŸ”— Computing πŸ”— Computing/Networking

Nagle's algorithm is a means of improving the efficiency of TCP/IP networks by reducing the number of packets that need to be sent over the network. It was defined by John Nagle while working for Ford Aerospace. It was published in 1984 as a Request for Comments (RFC) with title Congestion Control in IP/TCP Internetworks in RFCΒ 896.

The RFC describes what he called the "small-packet problem", where an application repeatedly emits data in small chunks, frequently only 1 byte in size. Since TCP packets have a 40-byte header (20 bytes for TCP, 20 bytes for IPv4), this results in a 41-byte packet for 1 byte of useful information, a huge overhead. This situation often occurs in Telnet sessions, where most keypresses generate a single byte of data that is transmitted immediately. Worse, over slow links, many such packets can be in transit at the same time, potentially leading to congestion collapse.

Nagle's algorithm works by combining a number of small outgoing messages and sending them all at once. Specifically, as long as there is a sent packet for which the sender has received no acknowledgment, the sender should keep buffering its output until it has a full packet's worth of output, thus allowing output to be sent all at once.

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