Chapter 9 Glossary of Terms
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Proxy server An older method of Internet connection sharing. Client in a local network
does not communicate directly with the target computer in the Internet but it passes
its request to a proxy server. The proxy server will process the request and deliver
the response.
SMTP Basic protocol used for e-mail delivery in the Internet. Sender and recipient are
identified by an e-mail address.
By default, TCP protocol and port 25 is used.
Service In network terminology, application used in an network environment is called
a service. In TCP/IP, the service is identified by a transport protocol and port (e.g.
HTTP uses TCP protocol and port 80).
SSL Protocol for secured and encrypted TCP connection. Originally, it was created to
secure the transmission of WWW pages by the HTTP protocol (this protocol is called
HTTPS). Today, almost all standard Internet services — SMTP, POP3, IMAP, LDAP, etc.
— supports SSL.
Communicatin starts by the exchange of an encryption key, which is later used for a
(symetrical) encryption of the real data.
TLS Transport Layer Security. SSL successor, de facto SSL version 4.