Second Level Domain
In the Domain Name System (DNS), the next lower level of the hierarchy underneath the top level domains. In a domain name, that portion of the domain name that appears immediately to the left of the .com, .net, .org, etc...) For example, the acehosts.com would be the second level domain for this web site. The top-level domain is .com.
Secondary Server
The name server will be used as a backup for the primary name server in the event that the primary server becomes unavailable.
Security Certificate
A chunk of information (often stored as a text file) that is used by the SSL protocol to establish a secure connection. Security Certificates contain information about who it belongs to, who it was issued by, a unique serial number or other unique identification, valid dates, and an encrypted ???fingerprint??? that can be used to verify the contents of the certificate. In order for an SSL connection to be created both sides must have a valid Security Certificate.
Server
A computer, or a software package, that provides a specific kind of service to client software running on other computers. It is basically a computer with the right tools required to "serve" others.
Server Side Includes (SSI)
Commands that can be included in web pages that are processed by the web server when a user requests a file. The command takes the form . A common use for SSI commands is to insert a universal menu into all of the pages of the web site so that the menu only has to be changed once and inserted with SSI instead of changing the menu on every page.
SLA
Service Level Agreement - A contract between the provider and the user that specifies the level of service that is expected during its term. SLAs are used by vendors and customers, as well as internally by IT shops and their end users. They can specify bandwidth availability, response times for routine and ad hoc queries and response time for problem resolution (network down, machine failure, etc.). SLAs can be very general or extremely detailed, including the steps taken in the event of a failure. For example, if the problem persists after 30 minutes, a supervisor is notified; after one hour, the account representative is contacted.
SLIP
(Serial Line Internet Protocol) A standard for using a regular telephone line (a serial line) and a modem to connect a computer as a real Internet site. SLIP is gradually being replaced by PPP .
SMTP
(Simple Mail Transport Protocol) -- The main protocol used to send electronic mail on the Internet. Most Internet email is sent and received using SMTP.
SNMP
(Simple Network Management Protocol) A set of standards for communication with devices connected to a TCP/IP network . Examples of these devices include routers , hubs, and switches. A device is said to be ???SNMP compatible??? if it can be monitored and/or controlled using SNMP messages. SNMP messages are known as ???PDU???s??? - Protocol Data Units. Devices that are SNMP compatible contain SNMP ???agent??? software to receive, send, and act upon SNMP messages. Software for managing devices via SNMP are available for every kind of commonly used computer and are often bundled along with the device they are designed to manage. Some SNMP software is designed to handle a wide variety of devices.
SQL
(Structured Query Language) A specialized programming language for sending queries to databases. Most industrial-strength and many smaller database applications can be addressed using SQL. Each specific application will have its own version of SQL implementing features unique to that application, but all SQL-capable databases support a common subset of SQL.
SSL
(Secure Sockets Layer) -- A protocol used to enable encrypted, authenticated communications across the Internet. SSL provides privacy, authentication, and message Integrity. In an SSL connection each side of the connection must have a Security Certificate, which each side's software sends to the other to ensure ultimate security. URL's that begin with "https" indicate that an SSL connection will be used.
