When ordering a Virtual Private Server (VPS), you either get access to it using a root login or a user with the provided password. Either way, you will need to change the password and create your own user.

User setup Link to heading

Username and password (received by email or via the hosting services console interface).
adduser username
Add it to sudo group:
usermod -aG sudo username

Remove old user:
sudo deluser username
Log in the new user
su - username

Securing SSH Link to heading

Now’s the time to secure our SSH install to disallow anything but public key authentication.
Generate SSH key for the current user.
ssh-keygen
Ensure your user has the right permissions:
chmod -R go= ~/.ssh
chown -R username:username ~/.ssh
Then you’ll want to edit SSH config file in order to secure your install:
sudo nano /etc/ssh/sshd_config

...
PermitRootLogin no
...
PubkeyAuthentication yes
...
PasswordAuthentication no
...

For extra security you can also change the port used to connect via SSH:
From #Port 22
To Port 99
From now on, you will be able to connect through ssh -p 99 username@xx.xx.xx.xx
Then enter the following commands to set up your firewall:

sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw allow ssh
sudo ufw allow 22
sudo ufw enable
sudo ufw status verbose
sudo ufw allow http
sudo ufw allow https
sudo ufw reload

Include IPV6 in the firewall rules
# Set to yes to apply rules
# to support IPv6 (no means only IPv6 on loopback accepted).
# You will need to 'disable' and then 'enable' the firewall for the changes to take affect.
IPV6=yes

Verify that hosts contains this configuration, editing /etc/hosts:

127.0.1.1 machine_name
127.0.0.1 localhost.localdomain localhost machine_name

Then /etc/hostname:
machine_name

Firewalling Link to heading

sudo apt install ufw
sudo nano /etc/default/ufw

Banning IPs trying to get inside your VPS Link to heading

We can now install Fail2Ban in order to ban IP addresses trying to force their way onto our machines through SSH protocols.

sudo apt install fail2ban
sudo apt install sendmail
sudo sendmailconfig

Type “Y” to answer all questions

sudo systemctl enable fail2ban
sudo systemctl start fail2ban
sudo systemctl status fail2ban

Edit /etc/fail2ban/jail.conf

Under [sshd] add:

[sshd]
logpath = %(sshd_log)s
filter = sshd
backend = systemd
enabled = true
port = 22
destemail = root@<fq-hostname>
sender = root@<fq-hostname>
ignoreip = 127.0.0.1/8 # add any static IP address you will connect from
action = %(action_mwl)s
mta = sendmail
maxretry = 3
findtime = 300
bantime = 3600

sudo systemctl restart fail2ban

Domain name Link to heading

Now onto making your domain name stick to your IP address. This should work with any DNS service, however interface might differ.
Delete Porkbun records.
In your domain DNS manager:
Type A - Address record
Leave Host blank
Add the IP address of your server to Answer (that’s what it’s called on Porkbun):
xx.xx.xx.xx
Do the same again:
Type A - Address record
But for Host add:
www
And your server’s IP address to Answer.
Zoho third party mail setup: Select MX (Mail Exchange record), add to Answer:
mail (or whatever subdomain or even domain you want people to see in your email address)
And to Priority:
10
Do the same for mx2.zoho.eu with Priority 20 and mx3.zoho.eu with Priority 30
MX your_domain.extension mx2.zoho.eu 600 20
MX your_domain.extension mx3.zoho.eu 600 50
MX your_domain.extension mx.zoho.eu 600 10
Zoho will ask you to input new DNS records, TXT - Text Record in order to link various features of your Zoho email account to your domain.
If it does not work, retry again.

Git configuration Link to heading 

git config --global user.name username
git config --global user.email username@email.com