Firewall

 A system or combination of systems that enforces a boundary between two or more networks. Gateway that limits access between networks in accordance with local security policy. The typical firewall is an inexpensive micro-based Unix box kept clean of critical data, with many modems and public network ports on it, but just one carefully watched connection back to the rest of the cluster. A collection of hardware and software components that supervises all traffic in and out of a network, permitting only traffic which is authorized by local security policy to pass. A firewall prevents outsiders from accessing your own private data resources and controls what outside resources its own users have access to. Basically, a firewall filters all network packets to determine whether to forward them toward their destination.
FTP File Transfer Protocol. A client/server protocol for exchanging files with a host computer.
Web Server An application that serves Web pages to Web browsers using the HTTP protocol. A computer where web pages and web server software are stored.
Web Proxy A server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control, and caching service.  A proxy server receives a request for an Internet service (such as a Web page request) from a user. If the proxy server is also a cache server, it can use its local cache of previously downloaded Web pages. to provide the page without forwarding the request to the Internet. If the page is not in the cache, the proxy server, uses one of its own IP addresses to request the page from the server out on the Internet. When the page is returned, the proxy server relates it to the original request and forwards it on to the user. To the user, all Internet requests and returned responses appear to be directly with the addressed Internet server.
NAT Network Address Translation. Allows a number of nodes on a network to access the Internet through a single IP address.
DVD Digital Versatile Disc Originally, Digital Video Disc. An optical storage medium that provides greater capacity and bandwidth than CD-ROM; DVDs are frequently used for multimedia as well as data storage.