Uniform resource identifier, uniform resource locator The symbolic address of a Web page or other Internet entity. The URI for this page is http://www.rossde.com/internet/intr_gloss.shtml. The URI beg [..]

User agent. The client used on the Internet, usually a browser or E-mail application. The brand and version of a user agent is usually indicated by the UA string, an identifier sent by the user agent [..]

Use a fake UA string to make a Web server act as if a browser being used is different from the actual browser (e.g., as if Opera were being used when actually Firefox is being used). Spoofing may be n [..]

See the discussion of this term: on my "Professional" Web Developers. on my Browser Sniffing: Detecting It, Dealing With It, and Defeating It.

Simple Mail Transfer Protocol, the interface used by an E-mail client to send outgoing E-mail messages. Actually, SMTP applies to both outgoing and incoming messages. However, many clients use POP (se [..]

A file used to establish a secure, authenticated connection between a user's computer and a Web site. A site certificate is used by a bank or other business to assure its customers that their Web [..]

Software that performs a task as requested by a client. In general, a server performs tasks such as searching a database or retrieving E-mail — tasks that require major computer power — while a client [..]

Point of presence (also termed PoP), the place where your phone line, T1 line, TV cable, et cetera connects to the Internet or where different ISPs connect to the backbone. When using a dial-up modem, [..]

Internet Service Provider, the company through which you connect to the Internet.

An E-mail server configured to accept and send messages from individuals who have not logged in (i.e., from users who are not on the server's user list). Since open relays appear to be the origin [..]