If you’re like most people, you probably use FTP to transfer files between your computer and a server. But if you’re new to FTP, there are a few things you need to know before starting to transfer files. First, FTP is a file sharing protocol. This means that it’s not just a way to transfer files between your computer and a server, but also a way for you to share files with other people. FTP is popular because it’s easy to use and can be used on both Windows and Macintosh computers. Second, FTP uses the Transmission Control Protocol (TCP) for its communication. TCP is the same protocol that’s used by email and other online communication services. This means that when you use FTP, your computer will always be able to connect to the server and send or receive data using TCP. Third, when you use FTP, you need to set up some basic permissions for your user account on the server. This will allow your computer to connect properly and send data over FTP without any problems. You can find more information about this process in the documentation provided with your server software.
FTP, or File Transfer Protocol, is a standard protocol for sending and receiving files from remote servers. It’s easier to use than command line alternatives like scp, especially with GUI interfaces like FileZilla.
What Is FTP?
In the olden days of the internet, public FTP servers were a very common way of making files available to a large number of people. Today, FTP is still around, and widely used for administrative tasks.
While some form of FTP CLI is shipped with most major operating systems, GUI clients like FileZilla make the process of moving files between servers as simple as dragging and dropping from local storage onto remote storage, or vice versa. All the underlying traffic is handled using FTP.
Setting this up requires you to install and configure an FTP server, like vsftpd, on the remote machine you want to access.
It should be noted that users logged in via FTP will have access to your system, just like you do. There are steps you can take to mitigate these risks, such as whitelisting access and locking users to their home directories.
Installing vsftpd
To get started, install vsftpd from your distro’s package manager. For Debian-based systems like Ubuntu, that would be from apt:
Next, you’ll have to start the service and set it to run at boot time:
FTP has two primary methods of authentication:
Anonymous FTP, where anyone can log in with no password. This is used for public file sharing, and is disabled by default. Local User Login, which allows any user in /etc/passwd to access FTP using a username and password.
You’ll probably want to enable local user login, and keep anonymous access disabled. Signing into FTP using your user account will give you access to anything your account can access.
Open up /etc/vsftpd.conf in your favorite text editor, and change the following line to YES:
If you want to be able to upload files, change write_enable to YES as well:
With a restart of vsftpd (systemctl restart vsftpd), you should now be able to login to FTP using a client like FileZilla, or the CLI on your personal machine.
If you only want to enable FTP for specific users, you can whitelist access. Open up /etc/vsftpd.userlist, and add the names of each account you want to enable on seperate lines.
Then, add the following lines to /etc/vsftpd.conf:
This will restrict access to only the users defined in the userlist file, and deny all others.
If you don’t want users accessing files outside of their home directory, you can place them in a chroot jail, which will prevent them from interacting with any upper-level directories. You can enable this by uncommenting the following line in /etc/vsftpd.conf:
Restart vsftpd with systemctl restart vsftpd to apply the changes.
Setting Up FTPS
Standard FTP traffic is sent unencrypted like HTTP. This obviously isn’t great, so you should configure vsftpd to encrypt traffic with TLS.
To do so, generate a new key and sign a request with openssl:
vsftpd needs the password removed from this key, so copy the key and pass it back to openssl:
Finally, generate a TLS certificate using this key:
Copy the key and cert over to /etc/pki/tls/certs/:
Now that all the certs are set up, you can once again open up /etc/vsftpd.conf, and add the following lines:
Restart vsftpd with systemctl restart vsftpd to apply the changes.
