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Domain Name System
The Domain Name System (DNS) is a hierarchical and distributed name service that provides a naming system for computers, services, and other resources on the Internet or other Internet Protocol (IP) networks. It associates various information with ''domain names'' (identification (information), identification String (computer science), strings) assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985. The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating authoritative name servers for each domain. Network administrators may delegate authority over subdomains of their allocated name space to other name servers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Mockapetris
Paul V. Mockapetris (born 1948 in Boston, Massachusetts, US) is an American computer scientist and Internet pioneer, who invented the Internet Domain Name System (DNS). Education Mockapetris graduated from the Boston Latin School in 1966, received his bachelor's degrees in physics and electrical engineering from the Massachusetts Institute of Technology in 1971 and his doctorate in information and computer science from the University of California at Irvine in 1982."ISI Names Dr. Paul Mockapetris Visiting Scholar" , Information Sciences Institute, University of Southern California, 27 March 2003"Paul Mockapetris" ''Biology Daily'', 19 Augu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Address Space
In computing, an address space defines a range of discrete addresses, each of which may correspond to a network host, peripheral device, disk sector, a memory cell or other logical or physical entity. For software programs to save and retrieve stored data, each datum must have an address where it can be located. The number of address spaces available depends on the underlying address structure, which is usually limited by the computer architecture being used. Often an address space in a system with virtual memory corresponds to a highest level translation table, e.g., a segment table in IBM System/370. Address spaces are created by combining enough uniquely identified qualifiers to make an address unambiguous within the address space. For a person's physical address, the ''address space'' would be a combination of locations, such as a neighborhood, town, city, or country. Some elements of a data address space may be the same, but if any element in the address is different, ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
User Datagram Protocol
In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages (transported as datagrams in Network packet, packets) to other hosts on an Internet Protocol (IP) network. Within an IP network, UDP does not require prior communication to set up communication channels or data paths. UDP is a connectionless protocol, meaning that messages are sent without negotiating a connection and that UDP does not keep track of what it has sent. UDP provides checksums for data integrity, and port numbers for addressing different functions at the source and destination of the datagram. It has no Handshake (computing), handshaking dialogues and thus exposes the user's program to any Reliability (computer networking), unreliability of the underlying network; there is no guarantee of delivery, ordering, or duplicate protection. If error-correction facilities are needed at the network interface level, an applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zone File
A Domain Name System (DNS) zone file is a text file that describes a DNS zone. A DNS zone is a subset, often a single domain, of the hierarchical domain name structure of the DNS. The zone file contains mappings between domain names and IP addresses and other resources, organized in the form of text representations of resource records (RR). A zone file may be either a DNS master file, authoritatively describing a zone, or it may be used to list the contents of a DNS cache., ''Domain Names - Implementation and Specification'', P. Mockapetris, (November 1987) File format The format of a zone file is defined in (section 5) and (section 3.6.1). This format was originally used by the Berkeley Internet Name Domain (BIND) software package, but has been widely adopted by other DNS server software – though some of them (e.g. NSD, PowerDNS) are using the zone files only as a starting point to compile them into database format, see also Microsoft DNS with Active Directory-database ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domain Name System Blocklist
A Domain Name System blocklist, Domain Name System-based blackhole list, Domain Name System blacklist (DNSBL) or real-time blackhole list (RBL) is a service for operation of mail servers to perform a check via a Domain Name System (DNS) query whether a sending host's IP address is blacklisted for email spam. Most mail server software can be configured to check such lists, typically rejecting or flagging messages from such sites. A DNSBL is a software mechanism, rather than a specific list or policy. Dozens of DNSBLs exist. They use a wide array of criteria for listing and delisting addresses. These may include listing the addresses of zombie computers or other machines being used to send spam, Internet service providers (ISPs) who willingly host spammers, or those which have sent spam to a honeypot system. Since the creation of the first DNSBL in 1998, the operation and policies of these lists have frequently been controversial, both in Internet advocacy circles and occasional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unsolicited Email
Email spam, also referred to as junk email, spam mail, or simply spam, refers to unsolicited messages sent in bulk via email. The term originates from a Monty Python sketch, where the name of a canned meat product, "Spam," is used repetitively, mirroring the intrusive nature of unwanted emails. Since the early 1990s, spam has grown significantly, with estimates suggesting that by 2014, it comprised around 90% of all global email traffic. Spam is primarily a financial burden for the recipient, who may be required to manage, filter, or delete these unwanted messages. Since the expense of spam is mostly borne by the recipient, it is effectively a form of "postage due" advertising, where the recipient bears the cost of unsolicited messages. This cost imposed on recipients, without compensation from the sender, makes spam an example of a " negative externality" (a side effect of an activity that affects others who are not involved in the decision). The legal definition and status of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNSSEC
The Domain Name System Security Extensions (DNSSEC) is a suite of extension specifications by the Internet Engineering Task Force (IETF) for securing data exchanged in the Domain Name System ( DNS) in Internet Protocol ( IP) networks. The protocol provides cryptographic authentication of data, authenticated denial of existence, and data integrity, but not availability or confidentiality. Overview The original design of the Domain Name System did not include any security features. It was conceived only as a scalable distributed system. The Domain Name System Security Extensions (DNSSEC) attempt to add security, while maintaining backward compatibility. of 2004 documents some of the known threats to the DNS, and their solutions in DNSSEC. DNSSEC was designed to protect applications using DNS from accepting forged or manipulated DNS data, such as that created by DNS cache poisoning. All answers from DNSSEC protected zones are digitally signed. By checking the digital signature, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domain Name Alias
A Canonical Name (CNAME) record is a type of resource record in the Domain Name System (DNS) that maps one domain name (an alias) to another (the canonical name). This can prove convenient when running multiple services (like an FTP server ''and'' a web server, each running on different ports) from a single IP address. One can, for example, use CNAME records to point ''ftp.example.com'' and ''www.example.com'' to the DNS entry for ''example.com'', which in turn has an A record which points to the IP address. Then, if the IP address ever changes, one only has to record the change in one place within the network: in the DNS A record for ''example.com''. CNAME records must always point to another domain name, never directly to an IP address. Details DNS CNAME records are specified in and clarified in Section 10 of . CNAME records are handled specially in the domain name system and have several restrictions on their use. When a DNS resolver encounters a CNAME record while l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse DNS Lookup
In computer networks, a reverse DNS lookup or reverse DNS resolution (rDNS) is the querying technique of the Domain Name System (DNS) to determine the domain name associated with an IP address – the reverse of the usual "forward" DNS lookup of an IP address from a domain name. The process of reverse resolving of an IP address uses PTR records. rDNS involves searching domain name registry and registrar tables. The reverse DNS database of the Internet is rooted in the .arpa top-level domain. Although the informationaRFC 1912 (Section 2.1)recommends that "every Internet-reachable host should have a name" and that "for every IP address, there should be a matching PTR record," it is not an Internet Standard requirement, and not all IP addresses have a reverse entry. Historical usage The modern "reverse DNS lookup" should not be confused with the now-obsolete "inverse query" (IQUERY) mechanism specified in : The IQUERY message type was always "optional" and "never achieved wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mail Exchanger
Within the Internet email system, a message transfer agent (MTA), mail transfer agent, or mail relay is software that transfers electronic mail messages from one computer to another using the Simple Mail Transfer Protocol. In some contexts, the alternative names mail server, mail exchanger, or MX host are used to describe an MTA. Messages exchanged across networks are passed between mail servers, including any attached data files (such as images, multimedia, or documents). These servers often keep mailboxes for email. Access to this email by end users is typically either by webmail or an email client. Operation A message transfer agent receives mail from either another MTA, a mail submission agent (MSA), or a mail user agent (MUA). The transmission details are specified by the Simple Mail Transfer Protocol (SMTP). When a recipient mailbox of a message is not hosted locally, the message is relayed, that is, forwarded to another MTA. Every time an MTA receives an email message, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMTP
The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and typically submit outgoing email to the mail server on port 465 or 587 per . For retrieving messages, IMAP (which replaced the older POP3) is standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync. SMTP's origins began in 1980, building on concepts implemented on the ARPANET since 1971. It has been updated, modified and extended multiple times. The protocol version in common use today has extensible structure with various extensions for authentication, encryption, binary data transfer, and internationalized email addresses. SMTP servers commonly use the Transmission Control Protocol on port number 25 (between ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AAAA Record
This list of DNS record types is an overview of resource records (RRs) permissible in zone files of the Domain Name System The Domain Name System (DNS) is a hierarchical and distributed name service that provides a naming system for computers, services, and other resources on the Internet or other Internet Protocol (IP) networks. It associates various information ... (DNS). It also contains pseudo-RRs. Resource records Other types and pseudo-RRs Other types of records simply provide some types of information (for example, an HINFO record gives a description of the type of computer/OS a host uses), or others return data used in experimental features. The "type" field is also used in the protocol for various operations. Obsolete record types Progress has rendered some of the originally defined record-types obsolete. Of the records listed at IANA, some have limited use, for various reasons. Some are marked obsolete in the list, some are for very obscure services, some are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
