A network protocol that allows a user to log in to a remote machine securely. cPanel & WHM can create keys to authenticate a user’s identity during SSH login, and allows users to manage SSH keys.
A newer version of SSL. Both are cryptographic schemes that allow for secure interaction between a browser and a web server.
SSL/TLS should protect all sensitive data (for example, credit card numbers) that you transmit over the internet.
Website owners can install an SSL certificate on a website in WHM’s Install an SSL Certificate on a Domain interface (WHM » Home » SSL/TLS » Install a SSL Certificate on a Domain) to allow SSL/TLS to protect the site.
A feature that allows a recipient server to verify that the domain specified in the From: field really sent the email message.
Enable SPF to prevent your server from replying to spam that forged your domain name as part of the sender’s address.
SPF only functions if both the sending and receiving mail servers use SPF.
Note:
On servers that run the AlmaLinux OS operating system, you may see a named warning about the absence of SPF resource records on DNS. This warning is not relevant on these servers because RFC 7208 deprecated SPF records. AlmaLinux OS servers use TXT records instead of SPF records.
Server Name Indication (SNI)
Allows clients to request a specific hostname at the beginning of the handshake process. In our documentation, SNI refers to this protocol in relation to Apache, while Mail SNI refers to this protocol in relation to Exim.
Server Profile
A collection of server roles that allow you to optimize a server to perform a specific task or function.
For example, the Mail Node profile lets you provide only the services and cPanel & WHM features that allow the system to serve mail.
You can select a server profile in WHM’s Server Profile interface (WHM » Home » Server Configuration » Server Profile).
Server Roles
A collection of services that provide specific server functionality. For example, the DNS role allows users to create and edit DNS zone files. This role consists of the bind, named, nds, pdns, and powerdns services.
In computing, a piece of software that monitors the processes and services on a machine. You can enable and disable services with WHM’s Service Manager interface (WHM » Home » Service Configuration » Service Manager).
Service Proxying
Service proxying configures local services to proxy requests for a cPanel account’s domains to a remote server. For more information, read our Service Proxying documentation.
Session (Login Session)
The period of activity between when you log in to and log out of an account or service. Each cPanel & WHM session generates a new security token that is only valid during that session.
Shell Fork Bomb
A malicious process that creates a cascade of new processes in order to use a server’s system resources, which, in effect, crashes the server. WHM’s Shell Fork Bomb Protection interface (WHM » Home » Security Center » Shell Fork Bomb Protection) offers a protective service from shell fork bombs.
Simple Mail Transfer Protocol (SMTP)
This protocol is the standard by which you transmit email messages across the internet. Use SMTP to send mail to a mail server’s Mail Transfer Agent (MTA).
Skeleton Directory
A directory that defines which files and subdirectories new accounts own by default.
When you create an account, the new user’s account contains an exact copy of the skeleton directory.
You can create these directories in WHM’s Skeleton Directory interface (WHM » Home » Account Functions » Skeleton Directory).
Smart Host
A type of email relay server. A smart host permits an SMTP server to send emails to an intermediate mail server before it sends messages to their final destination.
SolusVM
A GUI-based virtual private server (VPS) management system.
More:
For more information, read the SolusVM documentation.
SourceGuardian
PHP loaders that utilize a binary byte code and, sometimes, multiple levels of encryption. You can select a PHP loader in WHM’s Tweak Settings interface (WHM » Home » Server Configuration » Tweak Settings).
Unsolicited email that an automated system sends in bulk. Because recipients consider spam to be a costly nuisance, cPanel & WHM includes features like Apache SpamAssassin and BoxTrapper that can reduce the amount of spam that you receive.
Spam Box
The directory in which Apache SpamAssassin stores spam messages when you enable the Spam Box feature. Generally, the system stores these messages in the spam folder for the email account.
Spam Score
A value that Apache SpamAssassin assigns to every email message, based on the number of spam-related traits within the message. The higher a message’s spam score, the more likely it is to be spam. Spam filters let you specify what the system does with these messages.
Spoof
An attack in which attackers appear as another user through the falsification of data, in order to conceal their identities. Enable SPF to make it more difficult for spammers to spoof a domain.
Sprite
A type of file that can incorporate several different images. The cPanel interface uses sprites to decrease load time. When you add an icon, cPanel adds it to the appropriate sprite file.
SQL Database
A type of relational database management system.
SSL Certificate
An electronic document that binds a public key to an identity that consists of an email address, company, and location. This electronic document is a key piece in an authentication process.
More:
For more information, read our Guide to SSL documentation.
STABLE
One of cPanel & WHM’s release tiers. Versions on this tier have received considerable public exposure, testing, and verification.
cPanel account users can create subaccounts that use the same login and password information for email, FTP, and Web Disk services.
The system maintains password synchronization between each of the subaccount’s allowed services.
Users can manage subaccounts with cPanel’s User Manager interface (cPanel » Home » Preferences » User Manager).
Subdomain
A subsection of a website that exists as a subdirectory in the website owner’s home folder. For example, for the example.com domain, the subdomain URL could appear as subdomain.example.com. You can add and manage subdomains in cPanel’s Domains interface (cPanel » Home » Domains » Domains).
suEXEC
An Apache feature that allows users to run CGI and SSI applications on the system as themselves. By default, the system account (the nobody account with a UID of 99) executes CGI and SSI.
T
Tar
A program that collates files for transfer or distribution. The system usually compresses files that this program processes into tarballs.
Tarball
A file that the tar program collates and, usually, compresses.
Team Owner
The cPanel account that manages all team user accounts in the Manage Team interface (cPanel » Home » Manage Team).
Team User
A virtual account that exists under the team owner’s account in the Manage Team interface (cPanel » Home » Manage Team).
Telnet
A network protocol that allows a user to log in to a remote machine user account remotely. Telnet is similar to SSH, but is less secure. Don’t use Telnet to connect to your website except for testing purposes. Telnet sends login information as plain text, which others can easily intercept.
Template Toolkit (Perl Template Toolkit)
A Perl library template processing system that we use to create templates for all of the cPanel and WHM interfaces.
A unit of measure for digital memory storage. Generally, for the purposes of this documentation, one terabyte is a tebibyte, equal to 1,024 gigabytes.
Theme
A skeletal framework of interfaces, over which the system applies one of that theme’s styles.
cPanel & WHM currently ships with one default cPanel theme and one default WHM theme, as well as Webmail and login themes. To customize the default cPanel theme, use the Customization interface (WHM » Home » cPanel » Customization).
Use WHM’s Theme Manager interface (WHM » Home » Themes » Theme Manager) to install, preview, clone, download, and delete custom themes for the cPanel, Login, and Webmail interfaces.
Thumbnail
A smaller version of an image file that lets you easily view multiple images.
Time to Live (TTL)
A value that specifies how long clients will cache DNS zone data. You can view this information in WHM’s DNS Zone Manager interface (WHM » Home » DNS Functions » DNS Zone Manager).
Trojan Horse (Trojan)
Software that claims to perform one function but secretly performs malicious functions.
Trust Key Relationship
A cryptographic scheme that involves a public and private key pair.
Two-Factor Authentication (2FA)
An improved security measure that requires two forms of user identification: a password and a generated security code. When you enable 2FA, an application on your smartphone will supply a generated security code for authorization.
Users can configure 2FA in cPanel’s Two-Factor Authentication interface (cPanel » Home » Security » Two-Factor Authentication) and in the Webmail interface.
Server administrators can manage 2FA in WHM’s Two-Factor Authentication interface (WHM » Home » Security Center » Two-Factor Authentication).
U
Ubuntu
An open-source Linux operating system distribution based on Debian. Ubuntu is one of cPanel & WHM’s supported operating systems.
A connectionless transport protocol that works in conjunction with the Internet Protocol (IP). UDP transfers small units of data that require little reassembly, because it does not transmit data packets in a sequential order. It primarily broadcasts messages over a network. DNS lookups use UDP.
User ID (UID)
The unique user number that the system assigns to each user during a session. Notable UIDs include:
0 — root, the top-level system user. To find all of the users with this UID, run the grep :x:0: /etc/passwd command.
99 — nobody, the default executor of CGI scripts, if suEXEC is disabled. The system reserves UIDs 0 through 100 for system accounts like admin and root.
User Analytics ID
The User Analytics ID is assigned to each cPanel account user for use with interface analytics.
Unbound
A DNS resolver that performs caching and DNSSEC validation. This uses the libunbound library, which runs separately and can convert hostnames to IP addresses and perform other tasks using DNS information.
Uniform Resource Identifier (URI)
A string of characters that identifies a website. Some information uses URI synonymously with the terms URL and web address, though technical differences exist between the three terms.
Uniform Resource Locator (URL)
A string of characters that identifies the location of a website. Some information uses URL synonymously with the terms URI and web address, though technical differences exist between the three terms.
Unix Time
Unix time measures the number of seconds that have passed since the January 1, 1970 in UTC.
URI Encoding
Encodes information within a Uniform Resource Identifier (URI). In URI encoding, you must convert characters that browsers reserve for URL formatting into percent-encoded characters (for example, encode the forward slash (/) as %2F).
A person who uses a computer to accomplish some purpose.
UUID (Universally Unique Identifier)
A value that the system uses to identify a resource, similar to GUID. UUID is the more common identifier while Microsoft products are the main users of GUID.
V
Virtual Private Server (VPS)
A virtualized server. A single physical server can host multiple VPSs, each of which run their own instances of an operating system. This allows each VPS to have a separate root or superuser account, and to operate independently.
VirtualHost
A method to host multiple domains on a single server and sometimes on a single IP address.
A cPanel feature that allows website owners to drag and drop files to manipulate them through cPanel’s Web Disk interface (cPanel » Home » Files » Web Disk).
Web Server
A program, such as Apache, which receives requests from clients (browsers), retrieves the requested webpages, and serves them.
Webalizer
A program that displays various statistics for a website in tables and graphs.
Companion software to cPanel, which we design for hosting providers, resellers, and system administrators.
Webmail
Any application that allows website owners to access email through a browser. The main advantage to webmail is the ability to access the email account from any computer on the internet without the need to install or configure a specific mail program.
More:
For more information, read our Webmail documentation.
Wheel Group
A group of users who can execute the su and sudo commands on a Unix-based system, which allows them to become the root user. The su command requires the password for the root user, while the sudo command requires the user’s account password.
In BoxTrapper, a list of approved email senders. BoxTrapper automatically delivers messages from senders who are on the whitelist directly to the inbox.
In cPHulk, a list of approved IP addresses. cPHulk always allows logins to your server from IP addresses on the whitelist.
whmconf
This module creates a backup configuration containing WHM’s common settings that aren’t user-specific. For example, the settings from WHM’s Tweak Settings interface (WHM » Home » Server Configuration » Tweak Settings) and WHM’s Basic WebHost Manager Setup interface (WHM » Home » Server Configuration » Basic WebHost Manager Setup). The cpconftool script creates this configuration.
When you create a server backup file, the system creates a tarball that contains this data. The whmconf module creates the tarball in the whm-config-backup-cpanel__system__whmconf-11.86.0.9999-1577581839.tar.gz format, where 11.86.0.9999 is the cPanel & WHM version and 1577581839 is a Unix epoch timestamp.
whois
A Unix or Linux command that you can run on the command line to find out who owns a domain. For example, whois cpanel.net returns the ownership information for WebPros International, LLC’s website.
Wildcard Certificate
A certificate that lets you secure a domain with an unlimited number of subdomains, but each subdomain requires a dedicated IP address.
www
A symlink to the directory that holds the files for a website (~/public_html).
X
X-source Headers
Pieces of information that the system adds to email messages from a PHP script on your server, which detail the script’s location.
Enable these headers to help you locate insecure email scripts that spammers have abused.
You can enable these headers in WHM’s Tweak Settings interface (WHM » Home » Server Configuration » Tweak Settings).
Xen®
An open-source microkernel-designed hypervisor that allows for many instances of an operating system or different operating systems to run on a single host at the same time.
A high-performance filesystem for 64-bit servers. Servers that run the AlmaLinux OS or Ubuntu operating systems can use the XFS filesystem with cPanel & WHM.
Y
YAML Ain’t Markup Language or Yet Another Markup Language (YAML)
A markup language that allows developers to create documents that are both human- and machine-readable. Many of cPanel & WHM’s configuration files use this format.
Z
Zone (DNS Zone)
An administrative space or portion of the Domain Name System. This space directs internet traffic to the correct location. For example, example.com is a DNS zone whose servers direct its internet traffic.
Zone File (DNS Zone File)
A file on your server that primarily maps IP addresses to domain names. A correctly-configured zone file must exist in order for visitors to access your server from the internet.