Apache HTTP mod_ftp

1
Apache HTTP mod_ftp

• William A. Rowe, Jr.ASF Member, httpd and APR
  projectsSr. Software Engineer, Covalent
  Technologies

2
FTP Overview

• File Transfer Protocol (FTP) is an efficient
  protocol for transferring files over a TCP/IP
  network
• Unlike HTTP, FTP is designed to handle binary
  files directly without encoding and decoding data
• FTP session can be initiated over a command line,
  using graphical tools or via the Web Browser
• Need to have a login account on the FTP server
  machine, or login as anonymous
• Several FTP commands for manipulating files
• STOR, DELE, LIST, RMD, MKD etc.

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Shortcomings of traditional FTP

• Lacks in enterprise integration, security and
  performance
• Need to have a parallel management infrastructure
  for serving FTP
• User administration
• Logging, log rotation
• Security
• Many do not support FTP restart
• Monolithic architecture, missing extensibility

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mod_ftp overview

• Fully RFC Compliant FTP implementation powered by
  Apache 2.0 (RFC 959, 1123, 2228, 2389)?
• Leverages the new architecture of Apache 2,
  whereby content serving protocols are also
  modules now
• Same instance of Apache can serve FTP, Secure FTP
  as well as HTTP and HTTPS.
• Many FTP clients supported for SSL
• CuteFTP, WSFTP Pro etc.
• Supports FTP restart

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mod_ftp Additional Features

• FTP over SSL
• Extensive authentication and authorization
  support
• Dynamic content
• Robust and known API
• Allows for extensive expandability
• Leverages Apache web server popularity
• Extensible with module integration, mod_perl

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FTP over SSL

• mod_ftp leverages mod_ssl to encrypt traffic
• Digital Certificates (X.509)?
• Explicit SSL
• Server accepts both encrypted and unencrypted
  connections
• Implicit SSL
• Server accepts encrypted SSL connections only
• User must connect using SSL, port 990 by default

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Config Example

• ServerName ftphost.mydomain21
• ServerRoot /path/to/server/(ServerName)
• ServerAdmin webmaster_at_ftphost.mydomain
• DocumentRoot "/path/to/server/(ServerName)/ftpdoc
  s"
• ltDirectory /gt
• Options FollowSymLinks
• AllowOverride None
• lt/Directorygt
• ltDirectory "/path/to/server/(ServerName)/ftpdocs"
  gt
• ltLimit MKD RMD STOR DELE RNFRgt
• Order deny,allow
• Deny from all
• lt/Limitgt
• lt/Directorygt
• LoadModule ftp_module /path/modules/mod_ftp.so
• LogFormat "u a r" cmd_log
• LogFormat "b e HMS Yt T a B U M
  F d W u S Z Y" trans_log

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Config Example continued

• Listen 21
• ltVirtualHost _default_21gt
• DocumentRoot "/path/to/ftpdocs"
• FTP On
• ErrorLog logs/ftp_error_log
• CustomLog logs/ftp_command_log cmd_log
• CustomLog logs/ftp_transfer_log transfer_log
  envdo_trans_log
• ltDirectory "/path/to/ftpdocs"gt
• ltIfModule mod_authz_file.cgt
• AuthType Basic
• AuthName "FTP Authentication"
• AuthUserFile "/path/to/ftp_userfile"
• Require valid-user
• lt/IfModulegt
• lt/Directorygt
• lt/VirtualHostgt

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Good References

• http//httpd.apache.org/dev/dist/
• http//httpd.apache.org/modules/
• http//wiki.apache.org/httpd/
• http//en.wikipedia.org/wiki/Ftp_client

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Contact and Followup

• http//people.apache.org/wrowe/
• wrowe_at_rowe-clan.net
• IRC help at irc.freenode.net apache
• Peer help at users_at_httpd.apache.org