A SSL certificate will encrypt the communication between you and your server and/or between your servers in case you have backups and failover scripts, that's why this is an obligatory thing to do for all Delegates. Why? because if you don't have SSL you are sending your passphrase through the internet in plain text.
First thing you need to do is to have your own domain, it could be any domain. If you want to purchase at minimum $1 domain follow the great guide made by Gr33nDrag0n here : HowTo: Free SSL Certificate Creation and Configuration.
If you don't want to pay but still you want to have your own domain and SSL certificate follow this guide.
This guide will work with http://www.dot.tk/ you will get a free .tk domain name.
Search for a domain name
Go to http://www.dot.tk/ and start to search the name you want for your domain, in this guide we will use lisk-test.tk
Register your server's IP
Now, after you found your desired domain name, enter the IP of the server you want to register (this server needs to register in order to get a SSL certificate). First choose Use DNS and enter the IP of your server.
At the bottom choose 12 months to extend the length of your registration.
The only thing dot.tk ask from you is to login to their services via Facebook or WindowsLive ID, or with your own email address. I chose email address.
Enter the characters you see in the picture to validate you are not a robot:
Then choose how you are going to register with dot.tk, at the bottom you will see: Use your email address to signup! click it and it will show you an input field to enter your email.
Managing your domain
After you confirm your email address you will be able to login and see your control panel.
To see or change your server's IP go to the option Manage Freenom DNS, there you can add more subdomains.
In the subdomains you can register other backup servers.
If you save this, as in the example, you will have: lisk-backup2.lisk-test.tk
How to get SSL certificate for free
Now you have your own domain, the next step is to generate your SSL certificate.
Go to the server you registered in .tk.
First you need to be familiar with UFW (Uncomplicated Firewall), here is a guide that will help you to understand it:UFW - First time with a firewall. After you have everything ready with ufw, you will need to install free-ssl script: https://github.com/mrgrshift/free-ssl and read Install trusted SSL certificate issued by Letsencrypt
Follow the steps of the installation process. Once you have done all the steps you will have your trusted SSL certificate.