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Hesiod (name Service)
In computing, the Hesiod name service originated in Project Athena (1983–1991). It uses DNS functionality to provide access to databases of information that change infrequently. In Unix environments it often serves to distribute information kept in the , , and files, among others. Frequently an LDAP server is used to distribute the same kind of information that Hesiod does. However, because Hesiod can leverage existing DNS servers, deploying it to a network is fairly easy. In a Unix-like system users usually have a line in the file for each local user like: foo:x:100:10:Foo Bar:/home/foo:/bin/sh This line is composed of seven colon-separated fields which hold the following data: # user login name (string); # password hash or "x" if shadow password file is in use (string); # user id (unsigned integer); # user's primary group id (unsigned integer); # Gecos field (four comma separated fields, string); # user home directory (string); # user login shell (string). This system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, engineering, mathematical, technological and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology and software engineering. The term "computing" is also synonymous with counting and calculating. In earlier times, it was used in reference to the action performed by mechanical computing machines, and before that, to human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. Computing is intimately tied to the representation of numbers, though mathematical conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix-like
A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like application is one that behaves like the corresponding Unix command or shell. Although there are general philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like. Some well-known examples of Unix-like operating systems include Linux and BSD. These systems are often used on servers, as well as on personal computers and other devices. Many popular applications, such as the Apache web server and the Bash shell, are also designed to be used on Unix-like systems. One of the key features of Unix-like systems is their ability to support multiple users and processes simultaneously. This allows users to run multipl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerberos (protocol)
Kerberos () is a computer-network authentication protocol that works on the basis of ''tickets'' to allow nodes communicating over a non-secure network to prove their identity to one another in a secure manner. Its designers aimed it primarily at a client–server model, and it provides mutual authentication—both the user and the server verify each other's identity. Kerberos protocol messages are protected against eavesdropping and replay attacks. Kerberos builds on symmetric-key cryptography and requires a trusted third party, and optionally may use public-key cryptography during certain phases of authentication.RFC 4556, abstract. Kerberos uses UDP port 88 by default. The protocol was named after the character '' Kerberos'' (or ''Cerberus'') from Greek mythology, the ferocious three-headed guard dog of Hades. History and development Massachusetts Institute of Technology (MIT) developed Kerberos in 1988 to protect network services provided by Project Athena. The protocol is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Information Service
The Network Information Service, or NIS (originally called Yellow Pages or YP), is a client–server directory service protocol for distributing system configuration data such as user and host names between computers on a computer network. Sun Microsystems developed the NIS; the technology is licensed to virtually all other Unix vendors. Because British Telecom PLC owned the name "Yellow Pages" as a registered trademark in the United Kingdom for its paper-based, commercial telephone directory, Sun changed the name of its system to NIS, though all the commands and functions still start with "yp". A NIS/YP system maintains and distributes a central directory of user and group information, hostnames, e-mail aliases and other text-based tables of information in a computer network. For example, in a common UNIX environment, the list of users for identification is placed in and secret authentication hashes in . NIS adds another "global" user list which is used for identifying user ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Name Service Switch
The Name Service Switch (NSS) connects the computer with a variety of sources of common configuration databases and name resolution mechanisms. These sources include local operating system files (such as , , and ), the Domain Name System (DNS), the Network Information Service (NIS, NIS+), and LDAP. This operating system mechanism, used in billions of computers, including all Unix-like operating systems, is indispensable to functioning as part of the networked organization and the Internet. Among other things, it is invoked every time a computer user clicks on or types a website address in the web browser or responds to the password challenge to be authorized access to the computer and the Internet. nsswitch.conf A system administrator usually configures the operating system's name services using the file . This file lists databases (such as passwd, shadow and group), and one or more sources for obtaining that information. Examples for sources are ''files'' for local files, ''l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BIND
BIND () is a suite of software for interacting with the Domain Name System (DNS). Its most prominent component, named (pronounced ''name-dee'': , short for ''name daemon''), performs both of the main DNS server roles, acting as an authoritative name server for DNS zones and as a recursive resolver in the network. As of 2015, it is the most widely used domain name server software, and is the ''de facto'' standard on Unix-like operating systems. Also contained in the suite are various administration tools such as nsupdate and dig, and a DNS resolver interface library. The software was originally designed at the University of California, Berkeley (UCB) in the early 1980s. The name originates as an acronym of ''Berkeley Internet Name Domain'', reflecting the application's use within UCB. The latest version is BIND 9, first released in 2000 and still actively maintained by the Internet Systems Consortium (ISC) with new releases issued several times a year. Key features BIND 9 is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gecos Field
The gecos field, or GECOS field is a field in each record in the /etc/passwd file on Unix and similar operating systems. On UNIX, it is the 5th of 7 fields in a record. It is typically used to record general information about the account or its user(s) such as their real name and phone number. Format The typical format for the GECOS field is a comma-delimited list with this order: #User's full name (or application name, if the account is for a program) #Building and room number or contact person #Office telephone number #Home telephone number #Any other contact information (pager number, fax, external e-mail address, etc.) In most UNIX systems non-root users can change their own information using the ''chfn'' or ''chsh'' command. History Some early Unix systems at Bell Labs used GECOS machines for print spooling and various other services, so this field was added to carry information on a user's GECOS identity. Other uses On Internet Relay Chat (IRC), the real name field is some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shadow Password
passwd is a command on Unix, Plan 9, Inferno, and most Unix-like operating systems used to change a user's password. The password entered by the user is run through a key derivation function to create a hashed version of the new password, which is saved. Only the hashed version is stored; the entered password is not saved for security reasons. When the user logs on, the password entered by the user during the log on process is run through the same key derivation function and the resulting hashed version is compared with the saved version. If the hashes are identical, the entered password is considered to be correct, and the user is authenticated. In theory, it is possible for two different passwords to produce the same hash. However, cryptographic hash functions are designed in such a way that finding any password that produces the same hash is very difficult and practically infeasible, so if the produced hash matches the stored one, the user can be authenticated. The passwd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Name 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
/etc/group
In Unix-like systems, multiple users can be put into ''groups''. POSIX and conventional Unix file system permissions are organized into three classes, ''user'', ''group'', and ''others''. The use of groups allows additional abilities to be delegated in an organized fashion, such as access to disks, printers, and other peripherals. This method, among others, also enables the superuser to delegate some administrative tasks to normal users, similar to the ''Administrators'' group on Microsoft Windows NT and its derivatives. A group identifier, often abbreviated to GID, is a numeric value used to represent a specific group. The range of values for a GID varies amongst different systems; at the very least, a GID can be between 0 and 32,767, with one restriction: the login group for the superuser must have GID 0. This numeric value is used to refer to groups in the /etc/passwd and /etc/group files or their equivalents. Shadow password files and Network Information Service also refer to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
/etc/passwd
passwd is a command on Unix, Plan 9, Inferno, and most Unix-like operating systems used to change a user's password. The password entered by the user is run through a key derivation function to create a hashed version of the new password, which is saved. Only the hashed version is stored; the entered password is not saved for security reasons. When the user logs on, the password entered by the user during the log on process is run through the same key derivation function and the resulting hashed version is compared with the saved version. If the hashes are identical, the entered password is considered to be correct, and the user is authenticated. In theory, it is possible for two different passwords to produce the same hash. However, cryptographic hash functions are designed in such a way that finding any password that produces the same hash is very difficult and practically infeasible, so if the produced hash matches the stored one, the user can be authenticated. The passwd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
