X400
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X400
X.400 is a suite of ITU-T Recommendations that defines the ITU-T Message Handling System (MHS). At one time, the designers of X.400 were expecting it to be the predominant form of email, but this role has been taken by the SMTP-based Internet e-mail. Despite this, it has been widely used within organizations and was a core part of Microsoft Exchange Server until 2006; variants continue to be important in military and aviation contexts. History The first X.400 Recommendations were published in 1984 (''Red Book''), and a substantially revised version was published in 1988 (''Blue Book''). New features were added in 1992 (''White Book'') and subsequent updates. Although X.400 was originally designed to run over the OSI transport service, an adaptation to allow operation over TCP/IP, RFC 1006, has become the most popular way to run X.400. Developed in cooperation with ISO/IEC, the X.400-series recommendations specify OSI standard protocols for exchanging and addressing electronic ...
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ITU-T
The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Communication Technology such as X.509 for cybersecurity, Y.3172 and Y.3173 for machine learning, and H.264/MPEG-4 AVC for video compression, between its Member States, Private Sector Members, and Academia Members. The first meeting of the World Telecommunication Standardization Assembly (WTSA), the sector's governing conference, took place on 1 March of that year. ITU-T has a permanent secretariat called the Telecommunication Standardization Bureau (TSB), which is based at the ITU headquarters in Geneva, Switzerland. The current director of the TSB is Chaesub Lee (of South Korea), whose first 4-year term commenced on 1 January 2015, and whose second 4-year term commenced on 1 January 2019. Chaesub Lee succeeded Malcolm Johnson (Director), Malc ...
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Government Open Systems Interconnection Profile
The Government Open Systems Interconnection Profile (GOSIP) was a specification that profiled open networking products for procurement by governments in the late 1980s and early 1990s. Timeline * 1988 - GOSIP: Government Open Systems Interconnection Profile published by CCTA, an agency of UK government * 1988 - UK's CCTA commences work with France and West Germany on European Procurement Handbook (EPHOS) * 1990 - The US specification requiring Open Systems Interconnection (OSI) protocols was first published as Federal Information Processing Standards document FIPS 146-1. The requirement for US Government vendors to demonstrate their support for this profile led them to join the formal interoperability and conformance testing for networking products, which had been done by industry professionals at the annual InterOp show since 1980. * 1990 - Publication of European Procurement Handbook (EPHOS), intended to be a European GOSIP * 1991 - 4th and final version of UK GOSIP released * 19 ...
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British Telecom
BT Group plc (trade name, trading as BT and formerly British Telecom) is a British Multinational corporation, multinational telecommunications holding company headquartered in London, England. It has operations in around 180 countries and is the largest provider of Landline, fixed-line, Internet access, broadband and Mobile telephony, mobile services in the UK, and also provides Pay television, subscription television and Information technology, IT services. BT's origins date back to the founding in 1846 of the Electric Telegraph Company, the world's first public telegraph company, which developed a nationwide communications network. BT Group as it came to be started in 1912, when the General Post Office, a government department, took over the system of the National Telephone Company becoming the monopoly telecoms supplier in the United Kingdom. The Post Office Act of 1969 led to the GPO becoming a public corporation. The ''British Telecom'' brand was introduced in 1980, and be ...
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Active Directory
Active Directory (AD) is a directory service developed by Microsoft for Windows domain networks. It is included in most Windows Server operating systems as a set of processes and services. Initially, Active Directory was used only for centralized domain management. However, Active Directory eventually became an umbrella title for a broad range of directory-based identity-related services. A server running the Active Directory Domain Service (AD DS) role is called a domain controller. It authenticates and authorizes all users and computers in a Windows domain type network, assigning and enforcing security policies for all computers, and installing or updating software. For example, when a user logs into a computer that is part of a Windows domain, Active Directory checks the submitted username and password and determines whether the user is a system administrator or normal user. Also, it allows management and storage of information, provides authentication and authorization mec ...
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Lightweight Directory Access Protocol
The Lightweight Directory Access Protocol (LDAP ) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network. Directory services play an important role in developing intranet and Internet applications by allowing the sharing of information about users, systems, networks, services, and applications throughout the network. As examples, directory services may provide any organized set of records, often with a hierarchical structure, such as a corporate email directory. Similarly, a telephone directory is a list of subscribers with an address and a phone number. LDAP is specified in a series of Internet Engineering Task Force (IETF) Standard Track publications called Request for Comments (RFCs), using the description language ASN.1. The latest specification is Version 3, published aRFC 4511ref name="gracion Gracion.com. Retrieved on 2013-07-17. (a road map to the ...
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Replication (computing)
Replication in computing involves sharing information so as to ensure consistency between redundant resources, such as software or hardware components, to improve reliability, fault-tolerance, or accessibility. Terminology Replication in computing can refer to: * ''Data replication'', where the same data is stored on multiple storage devices * ''Computation replication'', where the same computing task is executed many times. Computational tasks may be: ** ''Replicated in space'', where tasks are executed on separate devices ** ''Replicated in time'', where tasks are executed repeatedly on a single device Replication in space or in time is often linked to scheduling algorithms. Access to a replicated entity is typically uniform with access to a single non-replicated entity. The replication itself should be transparent to an external user. In a failure scenario, a failover of replicas should be hidden as much as possible with respect to quality of service. Computer scientis ...
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Directory Service
In computing, a directory service or name service maps the names of network resources to their respective network addresses. It is a shared information infrastructure for locating, managing, administering and organizing everyday items and network resources, which can include volumes, folders, files, printers, users, groups, devices, telephone numbers and other objects. A directory service is a critical component of a network operating system. A directory server or name server is a server which provides such a service. Each resource on the network is considered an object by the directory server. Information about a particular resource is stored as a collection of attributes associated with that resource or object. A directory service defines a namespace for the network. The namespace is used to assign a ''name'' (unique identifier) to each of the objects. Directories typically have a set of rules determining how network resources are named and identified, which usually includes a req ...
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Business Card
Business cards are cards bearing business information about a company or individual. They are shared during formal introductions as a convenience and a memory aid. A business card typically includes the giver's name, company or business affiliation (usually with a logo) and contact information such as street addresses, telephone number(s), fax number, e-mail addresses and website. Before the advent of electronic communication business cards might also include telex details. Now they may include social media addresses such as Facebook, LinkedIn and Twitter. Traditionally, many cards were simple black text on white stock, and the distinctive look and feel of cards printed from an engraved plate was a desirable sign of professionalism. In the late 20th century, technological advances drove changes in style, and today a professional business card will often include one or more aspects of striking visual design. Prior to the COVID-19 pandemic, approximately 7 billion business car ...
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Gmail
Gmail is a free email service provided by Google. As of 2019, it had 1.5 billion active users worldwide. A user typically accesses Gmail in a web browser or the official mobile app. Google also supports the use of email clients via the POP and IMAP protocols. At its launch in 2004, Gmail provided a storage capacity of one gigabyte per user, which was significantly higher than its competitors offered at the time. Today, the service comes with 15 gigabytes of storage. Users can receive emails up to 50 megabytes in size, including attachments, while they can send emails up to 25 megabytes. In order to send larger files, users can insert files from Google Drive into the message. Gmail has a search-oriented interface and a "conversation view" similar to an Internet forum. The service is notable among website developers for its early adoption of Ajax. Google's mail servers automatically scan emails for multiple purposes, including to filter spam and malware, and to add context-s ...
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Dead Letter Office
Dead letter mail or undeliverable mail is mail that cannot be delivered to the addressee or returned to the sender. This is usually due to lack of compliance with postal regulations, an incomplete address and return address, or the inability to forward the mail when both correspondents move before the letter can be delivered. Largely based on the British model that emerged in the late eighteenth century, many countries developed similar systems for processing undeliverable mail. The term 'dead mail' is perhaps a misnomer, and several jurisdictions have opted for the use of the term 'undeliverable mail' as more clearly representing the status of the item whose transmission has been impeded. As it is performed by internal departments within postal administrations, little information about the dead letter office function has ever been made public. A few journal articles and at least one recently published book (Canadian) dealing with this topic have appeared. Classification as a ...
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Aeronautical Message Handling System
Air Traffic Services Message Handling Services (AMHS) is a standard for aeronautical ground-ground communications (e.g. for the transmission of NOTAM, Flight Plans or Meteorological Data) based on X.400 profiles. It has been defined by the ICAO. Levels of service ICAO Doc 9880 Part II defines two fundamental levels of service within the ATSMHS; * Basic ATSMHS and * the Extended ATSMHS. Additionally, ICAO Doc 9880 (Part II, section 3.4) outlines different subsets of the Extended ATSMHS. The Basic ATSMHS performs an operational role similar to the Aeronautical Fixed Telecommunication Network with a few enhancements. The Extended ATSMHS provided enhanced features but includes the Basic level of service capability; in this way it is ensured that users with Extended Service capabilities can inter-operate, at a basic level, with users having Basic Service capabilities and vice versa. The ATSMHS is provided by a set of end systems, which collectively comprise the ATS Message Handling ...
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Military Message Handling System
Military Message Handling System (MMHS) is a profile and set of extensions to X.400 for messaging in military environments. It is NATO standard STANAG 4406 and CCEB standard ACP 123. It adds to standard X.400 email support for military requirements such as mandatory access control (i.e. Classified/Secret/Top Secret messages and users, etc.). In particular it defines a new message format, P772 that is used in place of X.400's interpersonal message formats P2 (1984 standard) and P22 (1988 standard). MMHS specifications are implemented by several X.400 vendors, particularly those located in Europe, such as Raytheon UK, Boldon James, Deep-Secure, Thales Group, Nexor, Cassidian and Isode. Several RFC are supported: RFC 6477
- Registration of Military Message Handling System (MMHS) Header Fields for Use in Internet Mail


Implementations


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