Editing File Service Protocol

{{refimprove|date=January 2009}}

'''File Service Protocol''' ('''FSP''') is a [[User Datagram Protocol|UDP]]-based replacement for the [[File Transfer Protocol]], designed for anonymous access with lower hardware and network requirements than FTP.  In particular, because it uses UDP, it avoids the problems that many FTP servers have had with requiring a separate process for each client, {{citation needed|date=January 2014}} and because it is built to use an unreliable protocol, it can more easily{{citation needed|date=January 2014}} handle resuming a transfer after a network failure.

== History ==
FSP never reached the popularity of FTP for legitimate use (although [[WU-FTPD|wuarchive]] and [[id Software]] provided FSP service in addition to FTP for some time), but became very popular in the early-to-mid-1990s for [[Darknet|underground]] sites containing [[pornography]] and/or [[warez]].{{Citation needed|date=September 2008}} Because an FSP server only requires one process (as opposed to one process per client for most FTP servers), it is much harder for a [[system administrator]] to notice it in a process list; also, since it uses UDP, it is less likely to be noticed by a [[network administrator]].

Eventually, however, an increased use of [[Firewall (networking)|firewall]]s, a decreasing usage of the [[shell account]]s required to run a server or most of the clients, and a lack of FSP support in [[web browser]]s caused its use to taper off, and the [[warez scene]] moved to [[HTTP]] and [[File eXchange Protocol|FXP]] while pornography moved to publicly advertised [[web server]]s.{{Citation needed|date=September 2008}}

== Port number ==
As the FSP protocol is not officially recognized by [[Internet Assigned Numbers Authority|IANA]], it has no official [[List of TCP and UDP port numbers|port number]].  However, as a UDP equivalent of FTP, official FSP servers frequently run on UDP port 21, which is the same as FTP's TCP port number. Because FSP uses UDP and FTP uses TCP they can both run at same time on the same port number without conflict. Unofficial servers may run on any port, although 2121 was a popular choice.  (On most [[*nix]] systems, only the [[root user]] can start a process that listens on a port under 1024.)

== Protocol name ==
The name ''FSP'' was originally created without a real expansion.  In 1993, discussions were held about what to [[backronym|expand the acronym]] to; the ultimate result was ''File Service Protocol''.  Other suggestions included ''File Slurping Protocol'', ''FTP's Sexier Partner'', and ''Flaky Stream Protocol''.<ref>{{cite web |url=http://www.faqs.org/faqs/fsp-faq/part2/ |title=File Service Protocol (FSP) Frequently Asked Questions |work=[Part 2/2] Q.3.4 |publisher=FAQS.ORG |accessdate=13 January 2009}}</ref> Due to its inherent low performance,{{citation needed|date=January 2014}} FSP was sometimes colloquially said to stand for "Fucking Slow Protocol" .{{citation needed|date=January 2014}}

==References==
{{reflist}}

==External links==
* [http://fsp.sourceforge.net/ FSP Protocol Home Page]
* [http://www.faqs.org/faqs/fsp-faq/part1/ File Service Protocol (FSP) Frequently Asked Questions]
* [http://www.aes.id.au/?page_id=12 Comparisons of FSP with other FTP-like transfer protocols over Wi-Fi]
* {{Cite web|url=http://www.720k.net/|title=FSP ARCHIVE (File Service Protocol) Windows Clients, Servers, Apps|website=www.720k.net|access-date=2020-01-16}}

[[Category:Network file transfer protocols]]