Setup Pro-FTPD on Ubuntu 16.04 | 17.10 | 18.04 with SSL/TLS Certificates

By now you probably know FTP protocol is inherently insecure in its default form. A better method is to use FTP over SSH or SFTP. If you can’t setup SFTP, you next option should probably be FTP over SSL/TLS encryption or FTPS. and that’s what this post is going to show you.

When transferring files to a remote server, FTP is still one of the easiest ways to do it. However, when using FTP, it’s better to add some encryptions by using SSL/TLS protocols.

This post shows students and new users how to install and configure ProFTPD to use SSL/TLS certificates on Ubuntu 16.04 | 17.10 | 18.04 LTS server with encryption enabled.

The reasons you may want SSL/TLS enabled on FTP is that FTP communicates over insecure channel. and someone with the right tool could intercept data between the server and client read it. With SSL/TLS, even if the data is intercepted, they may still be unable to read the content, and that’s because of the extra security.

For this post, we’re going to be using a self-signed certificate. If you can afford public cert, then more power to you.

Step 1: Install ProFTPD on Ubuntu 18.04 LTS

To install ProFTPD on Ubuntu, run the commands below.

sudo apt update 
sudo apt-get install proftpd

During the installation, you should get a prompt with the message below: Select standalone

 ProFTPD can be run either as a service from inetd, or as a standalone server. Each choice has its own 
 benefits. With only a few FTP                                                                           
 connections per day, it is probably better to run ProFTPD from inetd in order to save resour                 
                
 On the other hand, with higher traffic, ProFTPD should run as a standalone server to avoid spawning 
 a new process for each incoming               
 connection.                                                                                                    
                                                                                                
 Run proftpd:                                                                                 
                                                                                                       
                                 from inetd                                                            
                                 standalone

After installing ProFTPD, the commands below can be used to stop, start and enable the server service to always start up when the server boots.

sudo systemctl stop proftpd.service
sudo systemctl start proftpd.service
sudo systemctl enable proftpd.service

Step 2: Create a Self-signed SSL/TLS certificate

Now that ProFTPD is installed, run the commands below to generate a self-signed SSL/TLS certificate for the server. the commands create a server key called proftpdserverkey.pem and store it in /etc/ssl/private and a certificate file called proftpdcertificate.pem in the /etc/ssl/certs.

sudo openssl req -x509 -nodes -newkey rsa:2048 -keyout /etc/ssl/private/proftpdserverkey.pem -out /etc/ssl/certs/proftpdcertificate.pem -days 365

After running the commands above, you’ll be prompted to answer few questions about the certificate you’re generating… answer them and complete the process.

Generating a 2048 bit RSA private key
...+++
.+++
writing new private key to '/etc/ssl/private/proftpdserverkey.pem'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:US
State or Province Name (full name) [Some-State]:New York
Locality Name (eg, city) []:Brooklyn
Organization Name (eg, company) [Internet Widgits Pty Ltd]:Website for Students
Organizational Unit Name (eg, section) []:SSL Unit
Common Name (e.g. server FQDN or YOUR name) []:example.com
Email Address []:webmaster@example.com

VSFTP server will use the key and certificate created above.

Step 3: Configuring ProFTPD to use SSL/TLS

Now that you’ve generated the server private key and certificate files, go and configure ProFTPD to use the SSL/TLS certificate created above. To do that, run the commands below to open ProFTPD default tls configuration file.

sudo nano /etc/proftpd/tls.conf

Then make the highlighted changes below so that the server can could communicate over SSL/TLS.

# This option specifies the location of the RSA certificate to use for SSL
# encrypted connections.
TLSRSACertificateFile /etc/ssl/certs/proftpdcertificate.pem
TLSRSACertificateKeyFile /etc/ssl/private/proftpdserverkey.pem
TLSEngine on
TLSLog /var/log/proftpd/tls.log
TLSProtocol SSLv23
TLSRequired on
TLSOptions NoCertRequest EnableDiags NoSessionReuseRequired
TLSVerifyClient off

Save your changes and restart the server.

Next, open ProFTPD default configuration file and comment out this line to include the tls.conf configurations.

sudo nano /etc/proftpd/proftpd.conf

uncomment the line as shown below:

# This is used for FTPS connections
#
Include /etc/proftpd/tls.conf

Save the file exit

Step 3: Restart ProFTPD Server

After adding the highlighted lines to the file, save it. Then run the commands below to restart ProFTPD server.

sudo systemctl restart proftpd

Now grab your favorite FTP client (FileZilla) and setup a new site in your site manage and use FTP protocol with encryption with explicit FTP over TLS. Type your username and password and connect.

You should be prompted with a certificate. accept the certificate and continue. You may check the box at the bottom of the page to trusted the certificate so you don’t get prompted in the future.