In May, 1974, the Institute of Electrical and Electronic Engineers
(IEEE) published a paper entitled "A Protocol for Packet Network
Interconnection". The paper described the Transmission Control
Protocol (TCP) and the Internet Protocol (IP). TCP
provides a connection orientated service, where as its sister, User
Datagram Protocol (UDP) provides a connectionless service. Both,
however, have a concept of ports, which range from 0 to 65535 -
many of which are reserved for specific uses. Operating systems
will tend to store these reserved, or well-known port numbers for
general use.
For example, you are (probably) reading this text with a web
browser such as firefox - the browser will have made a TCP
connection using port 80 to the geocaching web site in order to
download this description.
TCP/IP, UDP/IP and other protocols require a physical layer to
operate such as ethernet. You can even operate TCP over carrier
pigeon! ( see
http://www.blug.linux.no/rfc1149/
).
The internet as we know it today only works by co-operation - if
your PC used different protocols to other PC's or servers,
communication just wouldn't work. A large group of IT specialists
discuss and come to agreements (using published standards such as
RFCs) to ensure we are all
swimming in the same direction. We all owe these folks a large
thank you!
Anyway, back to the cache. You will find it at :-
N la-maint ° smtp . password-chg W 000 ° la-maint . netbios-dgm