A tag is a keyword or label that categorizes your question with other, similar questions.

Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.
38271 questions
Windows is the brand name for a series of operating systems from Microsoft. Current versions are Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, and Windows Server 2022. Instead of tagging a post "Windows", try to use a tag for a specific version.
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Version 2.2 of the Apache HTTP Server. When asking questions about virtualhosts, please include the output of the following command: "apache2ctl -S" (or "httpd -S" depending on your OS)
17280 questions
Nginx ("eNgine x") is a lightweight, high-performance HTTP server, reverse proxy, TCP stream proxy and mail proxy, released under a BSD-like license.
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Ubuntu Linux is a Debian derivative that aims to bring Linux mainstream. Questions on this site should generally refer to Ubuntu Server. Note that http://askubuntu.com is specifically dedicated to Ubuntu questions.
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Networking refers to the technologies and techniques that enable the interconnection of devices and applications allowing them to communicate electronically.
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The Domain Name System, usually referred to by the acronym DNS, is a hierarchical, distributed database where the keys are domain names. Questions involving publicly accessible domains should include the real, Fully Qualified Domain Name (FQDN)
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CentOS is a free (as in beer and speech) GNU/Linux distribution that is community driven and based on source code released from RedHat.
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A Microsoft technology that constitutes an LDAP directory service with centralized management functionality for user accounts, computer accounts, groups, and configuration management across many Windows servers and desktops.
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Windows Server 2008 is a Microsoft server operating system released in February 2008 and reached End Of Life on January 14, 2020. It is the successor to Windows Server 2003 and is based on the Windows Vista codebase. It was succeeded by Windows Server 2008 R2. This tag should only be used for questions related to Windows Server 2008. If your question is about Windows Server 2008 R2, please use the Windows-Server-2008-R2 tag.
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Secure Shell (SSH) is a protocol primarily for encrypted shell connections. This tag is also used for questions about sshd and openssh, the two standard applications for using SSH.
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MySQL is an open-source database owned by Oracle. ServerFault topics include how to run the server. For more MySQL specific questions like backup/restore/recovery/configuration, dba.stackexchange.com is probably a better home.
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Amazon Web Services (AWS) delivers a set of services that together form a reliable, scalable, and inexpensive computing platform "in the cloud". If you have a question about a specific web service, consider asking on its tag, e.g., amazon-ec2.
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PHP is a general-purpose scripting language that is especially suited for Web development. The online manual is an excellent resource for the language syntax and has an extensive list of the built-in and extension functions. Most extensions can be found in PECL.
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Debian is a popular and influential GNU/Linux distribution. Questions here should generally be about Debian Server.
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SSL and its successor, TLS, are encryption and authentication protocols that encrypt the full contents of a TCP connection, as well as potentially verifying the identities of the devices making the connection.
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For questions relating to application security and attacks against software. Please don't use this tag alone, that results in ambiguity. Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification, perusal, inspection, recording or destruction. If your question is not about a specific programming problem, please consider instead asking it at Information Security SE
6881 questions
iptables is the userspace command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators. Please, when asking a question about iptables, add the output from the following command: iptables -L -v -n
6626 questions
The server configuration of email, including POP3, SMTP, IMAP, and popular server software packages that control email.
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Amazon Elastic Compute Cloud (EC2) provides self-service, on-demand, pay-for-what-you-use computing infrastructure resources.
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Free and open source mail transfer agent (MTA) that routes and delivers email. When asking about postfix problem, please include the relevant maillog lines and output of the following command: `postconf -n` (non-default content of main.cf) and `postconf -M` (content of master.cf)
6398 questions
Version 2.4 of the Apache HTTPd Server. When asking questions about virtualhosts, please include the output of the following command: "apache2ctl -S" (or "httpd -S" depending on your OS)
5936 questions
Windows Server 2003 is a Microsoft server operating system released in April 2003, and reached End Of Life on July 14, 2015. It is the successor to Windows Server 2000 and is based on the Windows XP codebase. It was succeeded by Windows Server 2008.
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IIS is Internet Information Services, the web server included with Microsoft's Windows Server operating systems. This is a generic tag. Wherever possible please use a *version-specific* tag, such as [iis-7], [iis-7.5], etc.
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Windows Server 2008 R2 is an operating system from Microsoft, and reached End Of Life on January 14, 2020. It is an update of Windows Server 2008. Unlike Server 2003 R2, this R2 is a fully new Operating System. It is only available in 64-bit versions.
5290 questions
VPN is the acronym for Virtual Private Network - a network type that uses a the Internet to provide remote networks or single machines with secure access to their organization's network avoiding expensive leased lines.
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Questions related to Microsoft SQL Server. If your question is version specific please tag it specifically for that version as well. Does your SQL Server question belong here or on another site? Click the about the SQL Server tag link on the line below.
4775 questions
A Firewall is an application or hardware device used to inspect and filter network traffic.
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Docker is an open source project that automates the deployment of applications inside software containers.
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An interactive shell, scripting and programming language, and surrounding environment from Microsoft. Commonly used by system administrators managing Microsoft software (including Windows, Exchange, SharePoint, and cloud services Azure and Office 365), PowerShell is included by default with Windows, and takes over from previous languages such as VB Script.
4084 questions
Microsoft Azure is a Platform as a Service (PaaS) and Infrastructure as a Service (IaaS) cloud computing platform by Microsoft. Users of the platform can deploy their applications onto cloud hosting benefiting from on-demand service, elastic scale, and a highly managed environment on a pay-as-you-go basis.
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Windows Server 2012 R2 is a server operating system from Microsoft. It was published on May 31st of 2013, and will be End Of Life on Oct 10, 2023. It contains many substantial changes over it predecessor, and substantially streamlines the number of available versions, which are down to four: Foundation, Essentials, Standard and Datacenter.
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Making copies of data so that the copies may be used to restore the original after a data loss event, or for historical retention.
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the process by which data packets on communication networks are forwarded into the direction of their ultimate destination by routers.
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RAID, an acronym originally for Redundant Array of Inexpensive Disks (today usually interpreted as referred to as Redundant Array of Independent Disks), is a technology that provides increased storage performance and reliability through redundancy by spreading data across multiple disks using various algorithms (RAID-levels). RAID can be implemented in hardware storage controllers, or in software, usually as operating system/kernel features.
3655 questions
In computing, permissions (often called "privileges," "access rights" or just "rights") are rules associated with objects on a computer or network. Permissions determine which objects can access which objects, and to what extent.
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