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.
See Also: Certificate Authority , SSL

Server
A computer, or a software package, that provides a specific kind of service to client software running on other computers. The term can refer to a particular piece of software, such as a WWW server, or to the machine on which the software is running, e.g.Our mail server is down today, that’s why e-mail isn’t getting out. A single server machine could have several different server software packages running on it, thus providing many different servers to clients on the network.
See Also: Client , Network

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.
See Also: Internet , PPP

SMDS
(Switched Multimegabit Data Service) -- A new standard for very high-speed data transfer.

SMTP
(Simple Mail Transfer Protocol) -- The main protocol used to send electronic mail on the Internet.
SMTP consists of a set of rules for how a program sending mail and a program receiving mail should interact.

Almost all Internet email is sent and received by clients and servers using SMTP, thus if one wanted to set up an email server on the Internet one would look for email server software that supports SMTP.
See Also: Client , Server

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.
See Also: Network , Router

Spam (or Spamming)
An inappropriate attempt to use a mailing list, or USENET or other networked communications facility as if it was a broadcast medium (which it is not) by sending the same message to a large number of people who didn’t ask for it. The term probably comes from a famous Monty Python skit which featured the word spam repeated over and over. The term may also have come from someone’s low opinion of the food product with the same name, which is generally perceived as a generic content-free waste of resources. (Spam is a registered trademark of Hormel Corporation, for its processed meat product.)
E.g. Mary spammed 50 USENET groups by posting the same message to each.
See Also: Maillist , USENET

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 designed by Netscape Communications to enable encrypted, authenticated communications across the Internet.
SSL used mostly (but not exclusively) in communications between web browsers and web servers. URL’s that begin with “https” indicate that an SSL connection will be used.

SSL provides 3 important things: 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. Each side then encrypts what it sends using information from both its own and the other side’s Certificate, ensuring that only the intended recipient can de-crypt it, and that the other side can be sure the data came from the place it claims to have come from, and that the message has not been tampered with.
See Also: Browser , Server , Security Certificate , URL

Sysop
(System Operator) -- Anyone responsible for the physical operations of a computer system or network resource. A System Administrator decides how often backups and maintenance should be performed and the System Operator performs those tasks.