Difference between revisions of "SCP and SFTP"

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m (Setting up FTP with pure-ftpd: things in rc.d are started automatically in the daemons list, not modules)
(Added howto for setting up sftp with OpenSSH daemon.)
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= Introduction =
 
= Introduction =
  
'''SFTP''' (Secure File Transfer Protocol) encrypts passwords unlike plain FTP. SFTP is not really a true protocol, its just SSH + FTP or TLS/SSL + FTP . Note that there are many ways to set this up. This is one of them.  
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SFTP refers to various forms of (more or less) secure file transfer protocols. This article lists two examples and how to set them up.
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= SSH file transfer protocol =
 +
 
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[http://en.wikipedia.org/wiki/SSH_file_transfer_protocol SSH file transfer protocol] is a FTP-like protocol that allows secure file transfer and manipulation, encrypting both passwords and transfered data.
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== Setting up SSH file transfer protocol with OpenSSH ==
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Before setting up SFTP you should install and configure [[SSH#OpenSSH|OpenSSH]]. Once you have this running SFTP is very easy to set up.
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1. Open /etc/ssh/sshd_config with your favorite editor and add this line:
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Subsystem sftp /usr/lib/ssh/sftp-server
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2. Restart the SSH-daemon with:
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# /etc/rc.d/sshd restart
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 +
And it should work. You can access your files with the sftp program or [[sshfs]]. Many standard ftp programs should work as well.
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 +
= FTP over SSH =
 +
 
 +
[http://en.wikipedia.org/wiki/FTP_over_SSH#FTP_over_SSH_.28not_SFTP.29 FTP over SSH] encrypts passwords unlike plain FTP. FTP over SSH is not really a true protocol, its just SSH + FTP or TLS/SSL + FTP . Note that there are many ways to set this up. This is one of them.  
  
 
This setup in particular (using pure-ftpd + TLS) encrypts usernames, passwords, commands and server replies, but does NOT encrypt the data channel. This also means that that there is reduced performance cost on data transfer.  
 
This setup in particular (using pure-ftpd + TLS) encrypts usernames, passwords, commands and server replies, but does NOT encrypt the data channel. This also means that that there is reduced performance cost on data transfer.  
  
= Setting up FTP with pure-ftpd =
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== Setting up FTP with pure-ftpd ==
 
We will use pure-ftpd:
 
We will use pure-ftpd:
 
  # pacman -Sy pure-ftpd openssh openssl
 
  # pacman -Sy pure-ftpd openssh openssl
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and you can set it to automatically start by adding it to the daemons list in /etc/[[rc.conf]].
 
and you can set it to automatically start by adding it to the daemons list in /etc/[[rc.conf]].
  
= Set up Certicificates =
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== Set up Certicificates ==
 
Refer to http://download.pureftpd.org/pub/pure-ftpd/doc/README.TLS for more information. The short version is this:
 
Refer to http://download.pureftpd.org/pub/pure-ftpd/doc/README.TLS for more information. The short version is this:
  
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3. Be aware that using 1024 bits in some countries will get you the legal banhammer. Choose 512 or less if unsure.
 
3. Be aware that using 1024 bits in some countries will get you the legal banhammer. Choose 512 or less if unsure.
  
= Enable TLS =
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== Enable TLS ==
 
Towards the bottom of /etc/pure-ftpd.conf you should find a section for TLS. Uncomment and change the TLS setting to 1 (which enables both FTP and SFTP):
 
Towards the bottom of /etc/pure-ftpd.conf you should find a section for TLS. Uncomment and change the TLS setting to 1 (which enables both FTP and SFTP):
 
  TLS            1
 
  TLS            1
  
 
Now restart the pure-ftpd daemon and you should be able to login with sftp-enabled clients (e.g. FileZilla, SmartFTP). (Dont forget to use port 22.)
 
Now restart the pure-ftpd daemon and you should be able to login with sftp-enabled clients (e.g. FileZilla, SmartFTP). (Dont forget to use port 22.)

Revision as of 15:15, 23 January 2009


Introduction

SFTP refers to various forms of (more or less) secure file transfer protocols. This article lists two examples and how to set them up.

SSH file transfer protocol

SSH file transfer protocol is a FTP-like protocol that allows secure file transfer and manipulation, encrypting both passwords and transfered data.

Setting up SSH file transfer protocol with OpenSSH

Before setting up SFTP you should install and configure OpenSSH. Once you have this running SFTP is very easy to set up.

1. Open /etc/ssh/sshd_config with your favorite editor and add this line:

Subsystem sftp /usr/lib/ssh/sftp-server

2. Restart the SSH-daemon with:

# /etc/rc.d/sshd restart

And it should work. You can access your files with the sftp program or sshfs. Many standard ftp programs should work as well.

FTP over SSH

FTP over SSH encrypts passwords unlike plain FTP. FTP over SSH is not really a true protocol, its just SSH + FTP or TLS/SSL + FTP . Note that there are many ways to set this up. This is one of them.

This setup in particular (using pure-ftpd + TLS) encrypts usernames, passwords, commands and server replies, but does NOT encrypt the data channel. This also means that that there is reduced performance cost on data transfer.

Setting up FTP with pure-ftpd

We will use pure-ftpd:

# pacman -Sy pure-ftpd openssh openssl

Then you can go ahead and edit the configuration file:

# vi /etc/pure-ftpd.conf

You can start and stop the pure-ftpd daemon by

# /etc/rc.d/pure-ftpd start
# /etc/rc.d/pure-ftpd stop
# /etc/rc.d/pure-ftpd restart

and you can set it to automatically start by adding it to the daemons list in /etc/rc.conf.

Set up Certicificates

Refer to http://download.pureftpd.org/pub/pure-ftpd/doc/README.TLS for more information. The short version is this:

1. Create a Self-Signed Certificate:

# mkdir -p /etc/ssl/private
# openssl req -x509 -nodes -newkey rsa:1024 -keyout \
 /etc/ssl/private/pure-ftpd.pem \
 -out /etc/ssl/private/pure-ftpd.pem

2. Make it private:

# chmod 600 /etc/ssl/private/*.pem

3. Be aware that using 1024 bits in some countries will get you the legal banhammer. Choose 512 or less if unsure.

Enable TLS

Towards the bottom of /etc/pure-ftpd.conf you should find a section for TLS. Uncomment and change the TLS setting to 1 (which enables both FTP and SFTP):

TLS             1

Now restart the pure-ftpd daemon and you should be able to login with sftp-enabled clients (e.g. FileZilla, SmartFTP). (Dont forget to use port 22.)