Apple Filing Protocol
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The Apple Filing Protocol (AFP) is a network protocol allowing computers running Apple's Mac OS to access files over a network.
In "Classic" Mac OS (up to version 9.2.2) AFP is the only networked file system supported as standard. In Mac OS X, AFP is one of several networked file systems supported.
All versions of Mac OS since version 7.5 have been able to act as an AFP server, though this "Personal File Sharing" only supports a small number of connections and is intended for peer-to-peer use. Dedicated servers may run Apple's AppleShare server software on Classic Mac OS, or Mac OS X Server.
Third party server implementations of the AFP protocol are available from a number of companies. Microsoft includes AFP server support as an option in some versions of Windows and an open-source AFP server called Netatalk is available for Unix-like operating systems.
Earlier versions of AFP ran only on top of Apple's proprietary AppleTalk protocol stack but since version 2.1 AFP has run over TCP-IP.
Later revisions of the protocol also add support for large (>2GB) files and features of Mac OS X including long filenames (>31 characters) and UTF-8 characters in filenames.
AFP is the only networked file system which supports features of HFS (the standard filesystem in Mac OS) such as resource forks, type and creator codes and the desktop database. These features were integral to Classic Mac OS but are no longer essential under Mac OS X.
Security vulnerability
In late February, 2004, Apple reported (as cited in the NewsFactor article listed in the "References" section) a security vulnerability in the implementation of AFP in OS X, versions 10.2 through 10.3.2. When using network communication in those versions of OS X, an end-user may specify the preference of a secure shell tunnelled connection, but OS X will revert to cleartext authentication if the server fails to accept a secure shell connection. The flaw was discovered by Chris Adams, a system administrator in San Diego, California.
References
- Inside AppleTalk - original specification for the AppleTalk protocol stack including AFP (http://developer.apple.com/macos/opentransport/docs/dev/Inside_AppleTalk.pdf)
- Apple Filing Protocol Insecure Implementation (http://secunia.com/advisories/11012/)
- Glossary of Networking Terms (http://www.accsystems.com/glossary.htm)
- NewsFactor Network article, A (http://www.newsfactor.com/story.xhtml?story_title=How_Secure_Is_OS_X_&story_id=23467)