Secure File Transfer: SFTP Guide for Fast, Safe Remote File Management

Want to transfer files to a remote server securely? Ditch the outdated FTP! Learn how to use SFTP (Secure File Transfer Protocol) for encrypted file transfers, ensuring your data stays protected. This step-by-step guide will walk you through everything, from connecting to simple file manipulations.

Why SFTP? Secure File Transfer Protocol Explained

FTP, the traditional File Transfer Protocol, lacks encryption, making it vulnerable to eavesdropping. SFTP, built into SSH, provides a secure channel for transferring files. It leverages the same robust encryption as SSH, safeguarding your data during transit.

In short: SFTP is almost always a better more secure alternative to FTP!

Connect to Your Server Using SFTP

SFTP utilizes SSH for authentication, offering various secure connection methods. We strongly recommend using SSH keys for enhanced security.

Setting up SSH Keys

Generate an SSH key pair and transfer your public key to the server you want to access. If you can connect to your server via SSH, you're already set to use SFTP.

Test this by using the following command:

ssh sammy@your_server_ip_or_remote_hostname

Exit the SSH session by typing exit.

Initiating an SFTP Session

Establish an SFTP session with this command:

sftp sammy@your_server_ip_or_remote_hostname

This command connects you to the server and changes your command prompt to the SFTP prompt.

Connecting on a Custom Port

If your SSH server uses a custom port, specify it with the -oPort option:

sftp -oPort=custom_port sammy@your_server_ip_or_remote_hostname

This connects you to the remote server through your specified custom port.

Master the SFTP Command Line Interface

SFTP offers a command-line interface for managing your remote files. Here are some essential commands to get you started.

Getting Help

Type help or ? at the SFTP prompt to view a list of available commands.

Navigating the Remote and Local Filesystems

SFTP provides commands similar to standard shell commands for navigating the file system.

• pwd: Print the current directory on the remote server.
• ls: List the contents of the current remote directory.
• cd: Change the current directory on the remote server.
• lpwd: Print the local working directory.
• lls: List the contents of the current local directory.
• lcd: Change the current directory on the local machine.

Transferring Files Securely: Get and Put Commands

The core functionality of SFTP is transferring files between your local machine and the remote server.

Copying From Remote to Local (Download)

Use the get command to download files from the remote server:

get remoteFile localFile

The -r option downloads directories recursively:

get -r someDirectory

The -P or -p flag preserves permissions and access times:

get -Pr someDirectory

Copying From Local to Remote (Upload)

Use the put command to upload files to the remote server:

put localFile remoteFile

The -r option uploads directories recursively:

put -r localDirectory

Checking Disk Space

Ensure you have enough disk space before transferring files.

• df -h: Display disk space usage on the remote server.
• !df -h: Execute the df -h command on your local machine (use ! to execute commands locally).

Simple File Manipulation Tricks

SFTP allows basic file management tasks on the remote server.

• chown userID file: Change the owner of a file. Note: Requires the user ID (UID), not the username. Use get /etc/passwd and !less passwd as a workaround to find the UID.
• chgrp groupID file: Change the group owner of a file. Note: Requires the group ID (GID), not the group name. Use get /etc/group and !less group to find the GID.
• chmod 777 publicFile: Change file permissions (same as the standard chmod command).
• lumask 022: Set the local umask for downloaded files.
• mkdir directoryName: create directories on the remote server.
• lmkdir directoryName: create directories on the local machine.

Other file commands available include ln, rm, and rmdir, mirroring their shell counterparts.

Exiting the SFTP Session

Type exit or bye to terminate the SFTP session.

SFTP: A Secure Alternative

SFTP offers a secure and versatile way to transfer files. While not as feature-rich as modern shell tools, it excels in secure file transfer. Consider SFTP when security is paramount.