ICMP Time Exceeded
The Internet Control Message Protocol (ICMP) is a supporting protocol in the Internet protocol suite. It is used by network devices, including routers, to send error messages and operational information indicating success or failure when communicating with another IP address, for example, an error is indicated when a requested service is not available or that a host or router could not be reached. ICMP differs from transport protocols such as TCP and UDP in that it is not typically used to exchange data between systems, nor is it regularly employed by end-user network applications (with the exception of some diagnostic tools like ping and traceroute). ICMP for IPv4 is defined in RFC 792. A separate ICMPv6, defined by RFC 4443, is used with IPv6. Technical details ICMP is part of the Internet protocol suite as defined in RFC 792. ICMP messages are typically used for diagnostic or control purposes or generated in response to errors in IP operations (as specified in RFC 11 ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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DARPA
The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the Advanced Research Projects Agency (ARPA), the agency was created on February 7, 1958, by President Dwight D. Eisenhower in response to the Soviet Union, Soviet launching of Sputnik 1 in 1957. By collaborating with academia, industry, and government partners, DARPA formulates and executes research and development projects to expand the frontiers of technology and science, often beyond immediate U.S. military requirements.Dwight D. Eisenhower and Science & Technology, (2008). Dwight D. Eisenhower Memorial CommissionSource ''The Economist'' has called DARPA the agency "that shaped the modern world," and pointed out that "Moderna COVID-19 vaccine, Moderna's COVID-19 vaccine sits alongside weather satellites, Global Positioning System, GPS, Unmann ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Datagram
A datagram is a basic transfer unit associated with a packet-switched network. Datagrams are typically structured in header and payload sections. Datagrams provide a connectionless communication service across a packet-switched network. The delivery, arrival time, and order of arrival of datagrams need not be guaranteed by the network. History In the early 1970s, the term ''datagram'' was created by combining the words ''data'' and ''telegram'' by the CCITT rapporteur on packet switching, Halvor Bothner-By. While the word was new, the concept had already a long history. In 1962, Paul Baran described, in a RAND Corporation report, a hypothetical military network having to resist a nuclear attack. Small standardized "message blocks", bearing source and destination addresses, were stored and forwarded in computer nodes of a highly redundant meshed computer network. "The network user who has called up a "virtual connection" to an end station and has transmitted messages ... ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Ping Of Death
A ping of death is a type of attack on a computer system that involves sending a malformed or otherwise malicious ping to a computer. A correctly formed ping packet is typically 56 bytes in size, or 64 bytes when the Internet Control Message Protocol (ICMP) header is considered, and 84 bytes including Internet Protocol (IP) version 4 header. However, any IPv4 packet (including pings) may be as large as 65,535 bytes. Some computer systems were never designed to properly handle a ping packet larger than the maximum packet size because it violates the Internet Protocol. Like other large but well-formed packets, a ping of death is fragmented into groups of 8 octets before transmission. However, when the target computer reassembles the malformed packet, a buffer overflow can occur, causing a system crash and potentially allowing the injection of malicious code. In early implementations of TCP/IP, this bug is easy to exploit and can affect a wide varie ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Exploit (computer Security)
An exploit (from the English verb ''to exploit'', meaning "to use something to one’s own advantage") is a piece of software, a chunk of data, or a sequence of commands that takes advantage of a bug or vulnerability to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic (usually computerized). Such behavior frequently includes things like gaining control of a computer system, allowing privilege escalation, or a denial-of-service (DoS or related DDoS) attack. In lay terms, some exploit is akin to a 'hack'. Classification There are several methods of classifying exploits. The most common is by how the exploit communicates to the vulnerable software. A ''remote exploit'' works over a network and exploits the security vulnerability without any prior access to the vulnerable system. A ''local exploit'' requires prior access to the vulnerable system and usually increases the privileges of the person running the exploit past tho ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Header Rest
Header may refer to: Computers and engineering * Header (computing), supplemental data at the beginning of a data block ** E-mail header ** HTTP header * Header file, a text file used in computer programming (especially in C and C++) * A pin header is a mainly male style of electrical connector on printed circuit boards, including motherboards, providing links to external devices * Exhaust manifold, in automotive design Construction * Lintels (headers), structural members in light-frame construction which run perpendicular to floor and ceiling joists, "heading" them off to create an opening * Lintel (architecture), a structural member in post-and-lintel building construction * In brickwork, a brick laid with its short side exposed * In piping, a manifold or length of pipe that connects multiple smaller pipes Sports * Header (sailing): a term used in sailboat racing to denote a wind shift * Header, a herding dog with a specific method of interacting with its flock * Header, a he ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Header Checksum
A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data integrity but are not relied upon to verify data authenticity. The procedure which generates this checksum is called a checksum function or checksum algorithm. Depending on its design goals, a good checksum algorithm usually outputs a significantly different value, even for small changes made to the input. This is especially true of cryptographic hash functions, which may be used to detect many data corruption errors and verify overall data integrity; if the computed checksum for the current data input matches the stored value of a previously computed checksum, there is a very high probability the data has not been accidentally altered or corrupted. Checksum functions are related to hash functions, fingerprints, randomization functions, a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Header Code
Header may refer to: Computers and engineering * Header (computing), supplemental data at the beginning of a data block ** E-mail header ** HTTP header * Header file, a text file used in computer programming (especially in C and C++) * A pin header is a mainly male style of electrical connector on printed circuit boards, including motherboards, providing links to external devices * Exhaust manifold, in automotive design Construction * Lintels (headers), structural members in light-frame construction which run perpendicular to floor and ceiling joists, "heading" them off to create an opening * Lintel (architecture), a structural member in post-and-lintel building construction * In brickwork, a brick laid with its short side exposed * In piping, a manifold or length of pipe that connects multiple smaller pipes Sports * Header (sailing): a term used in sailboat racing to denote a wind shift * Header, a herding dog with a specific method of interacting with its flock * Header, a he ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Header Type
Header may refer to: Computers and engineering * Header (computing), supplemental data at the beginning of a data block ** E-mail header ** HTTP header * Header file, a text file used in computer programming (especially in C and C++) * A pin header is a mainly male style of electrical connector on printed circuit boards, including motherboards, providing links to external devices * Exhaust manifold, in automotive design Construction * Lintels (headers), structural members in light-frame construction which run perpendicular to floor and ceiling joists, "heading" them off to create an opening * Lintel (architecture), a structural member in post-and-lintel building construction * In brickwork, a brick laid with its short side exposed * In piping, a manifold or length of pipe that connects multiple smaller pipes Sports * Header (sailing): a term used in sailboat racing to denote a wind shift * Header, a herding dog with a specific method of interacting with its flock * Header, a he ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Octet (computing)
The octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, as the byte has historically been used for storage units of a variety of sizes. The term ''octad(e)'' for eight bits is no longer common. Definition The international standard IEC 60027-2, chapter 3.8.2, states that a byte is an octet of bits. However, the unit byte has historically been platform-dependent and has represented various storage sizes in the history of computing. Due to the influence of several major computer architectures and product lines, the byte became overwhelmingly associated with eight bits. This meaning of ''byte'' is codified in such standards as ISO/IEC 80000-13. While ''byte'' and ''octet'' are often used synonymously, those working with certain legacy systems are careful to avoid ambiguity. Octets can be represented using number systems of varying bases such as the hexadeci ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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List Of IP Protocol Numbers
This is a list of the IP protocol numbers found in the field ''Protocol'' of the IPv4 header and the ''Next Header'' field of the IPv6 header. It is an identifier for the encapsulated protocol and determines the layout of the data that immediately follows the header. Both fields are eight bits wide. Protocol numbers are maintained and published by the Internet Assigned Numbers Authority (IANA). {, class="wikitable" , - ! Hex ! Protocol Number !! Keyword !! Protocol !! References/RFC , - , 0x00 , 0 , HOPOPT , IPv6 Hop-by-Hop Option , , - , 0x01 , 1 , ICMP , Internet Control Message Protocol , , - , 0x02 , 2 , IGMP , Internet Group Management Protocol , , - , 0x03 , 3 , GGP , Gateway-to-Gateway Protocol , , - , 0x04 , 4 , IP-in-IP , IP in IP (encapsulation) , , - , 0x05 , 5 , ST , Internet Stream Protocol , , , - , 0x06 , 6 , TCP , Transmission Control Protocol , , - , 0x07 , 7 , CBT , Core-based trees , , - , 0x08 , 8 , EGP , Ex ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Transport Layer
In computer networking, the transport layer is a conceptual division of methods in the layered architecture of protocols in the network stack in the Internet protocol suite and the OSI model. The protocols of this layer provide end-to-end communication services for applications. It provides services such as connection-oriented communication, reliability, flow control, and multiplexing. The details of implementation and semantics of the transport layer of the Internet protocol suite, which is the foundation of the Internet, and the OSI model of general networking are different. The protocols in use today in this layer for the Internet all originated in the development of TCP/IP. In the OSI model the transport layer is often referred to as Layer 4, or L4, while numbered layers are not used in TCP/IP. The best-known transport protocol of the Internet protocol suite is the Transmission Control Protocol (TCP). It is used for connection-oriented transmissions, whereas the c ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Network Layer
In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing through intermediate routers. Functions The network layer provides the means of transferring variable-length network packets from a source to a destination host via one or more networks. Within the service layering semantics of the OSI network architecture, the network layer responds to service requests from the transport layer and issues service requests to the data link layer. Functions of the network layer include: ; Connectionless communication : For example, IP is connectionless, in that a data packet can travel from a sender to a recipient without the recipient having to send an acknowledgement. Connection-oriented protocols exist at other, higher layers of the OSI model. ; Host addressing :Every host in the network must have a unique address that determines where it is. This address is normally assigned from a hierar ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |