File Service Protocol

From Wikipedia, the free encyclopedia

File Service Protocol is a 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, and because it is built to use an unreliable protocol, it can more easily handle resuming a transfer after a network failure.

1 History
2 Port Number
3 Protocol Name
4 External links

[edit] History

FSP never reached the popularity of FTP for legitimate use (although 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 underground sites containing pornography and/or warez. As an FSP server only required one process (as opposed to one process per client for most FTP servers), it was much harder for a system administrator to notice it in a process list, and as it used UDP, it was less likely to be noticed by a network administrator.

Eventually, however, increased use of firewalls, a decreasing usage of the shell accounts required to run a server or most of the clients, and a lack of FSP support in web browsers caused its use to taper off, and the warez scene moved to HTTP and FXP while pornography moved to publicly-advertised web servers.

The protocol and programs that use it are once again under active development as of 2005, however, so it may see some resurgence.

[edit] Port Number

As the FSP protocol is not officially recognized by IANA, it has no official 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. Unofficial servers may run on any port, although 2121 was a popular choice.

[edit] Protocol Name

The name FSP was originally created without a real expansion. In 1993, discussions were held about what to 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.