from
The Free On-line Dictionary of Computing (8 July 2008)
stateless
A stateless {server} is one which treats each request as an
independent transaction, unrelated to any previous request.
This simplifies the server design because it does not need to
allocate storage to deal with conversations in progress or
worry about freeing it if a client dies in mid-transaction. A
disadvantage is that it may be necessary to include more
information in each request and this extra information will
need to be interpreted by the server each time.
An example of a stateless server is a {World-Wide Web} server.
These take in requests ({URLs}) which completely specify the
required document and do not require any context or memory of
previous requests.
Contrast this with a traditional {FTP} server which conducts
an interactive session with the user. A request to the server
for a file can assume that the user has been authenticated and
that the current directory and transfer mode have been set.