Initial Server Setup

(if it's a reinstall) remove server from known_hosts in .ssh folder
Create a new user and Grant access

It is not a good practice to use the root account apart from the initial server setup, so we create a new user, and give it appropriate access.
```
 adduser newUser
```
Update package repositories
```
apt update
apt upgrade -y
```
(if sudo is not installed) Install sudo, and add the new user to the sudo group. newUser is then put into the sudo group which members are allowed to use the sudo command in Debian
```
apt install sudo -y
usermod -aG sudo newUser
```
Setup firewall (ufw)
```
apt install ufw
```
check available profiles using the following command
```
ufw app list
```
OpenSSH should be on the list. It should come preinstalled on Debian 10. If not, check out Enable SSH Server on Debian 11

Then, allow traffic to and from OpenSSH
```
ufw allow OpenSSH
```
Enable the firewall
```
ufw enable
```
check the firewall status
```
ufw status
```
This confirms the firewall is on and allowing traffic to and from OpenSSH
(Optional) Top 8 Things to do after Installing Debian 10 (Buster)

(Optional) Setup SSH

Generate the key pair on the client (your computer) In windows powershell
```
ssh-keygen
```
Specify path and filename (.ssh in the home directory and id_rsa is the default path and filename respectively)

Enter a passphrase (highly recommended for security). If a passphrase is set, you'll be required to enter this for authentication.

Now the key pair is generated and saved in the directory specified.
Copy the public key (the generated file with .pub extension) to the server

In Windows Powershell, if /.ssh directory already exist in the user home directory. use this command to copy the public key to the server, replacing the filename, username, and server IP.
```
 cat ~/.ssh/key-filename.pub | ssh newUser@123.45.6.7 "cat >> ~/.ssh/authorized_keys"
```
Otherwise, if .ssh directory does not already exist, use the following
```
 cat ~/.ssh/key-filename.pub | ssh newUser@123.45.6.7 "mkdir ~/.ssh; cat >> ~/.ssh/authorized_keys"
```
Enter 'yes' to "Are you sure you want to continue connecting?" and the user password to continue.
If everything is setup correctly, we should be able to SSH into the server using the follow command. Enter the pass phrase set up earlier
```
 ssh newUser@123.45.6.7 -p 22  -i ~/.ssh/<filename>
```
(optional) To connect to the server without having to specify the identity file every time, edit /.ssh/config, add the following entry for the VPS. Using the same username, VPS IP and filename used above. "Host" can be anything descriptive
```
Host 123.45.6.7 (newUser)
  HostName 123.45.6.7
  User newUser
  IdentityFile ~/.ssh/<filename>
```
Now we can simply use the following command to connect to the server
```
ssh newUser@123.45.6.7
```

Setup the Web Server (Nginx)

Remember to Reload Nginx

sudo systemctl reload nginx

(Optional) Setup SSL

This is optional unless your TLD requires it, such as .dev

Let's Encrypt provides SSL certificate which lasts 3 months and can be set to automatically renewed using the certbot package.

How to Set Up SSH Keys on Debian 10

Add Subdomains

Create a new directory like /var/www/subdomain.mydomain.dev/html

Make a new file, subdomain.mydomain.dev in /etc/nginx/sites-available, with the following content

server {
listen 80;
listen [::]:80;

root /var/www/mydomain/html;
index index.html index.htm index.nginx-debian.html;

server_name mydomain www.mydomain;

location / {
 try_files $uri $uri/ =404;
}
}

Create symbolic link in sites-enabled

sudo ln -s /etc/nginx/sites-available/subdomain.mydomain.dev /etc/nginx/sites-enabled/

Add SSL Certificates with certbot We have to redo all the old and new domains and subdomains.

sudo certbot --nginx -d mydomain.dev -d www.mydomain.dev -d subdomain.mydomain.dev -d subdomain2.mydomain.dev

Restart nginx
```
sudo systemctl reload nginx
```

Setup VPS - Debian, Nginx, with subdomains

Resources and Notes

Table of contents

Initial Server Setup

(Optional) Setup SSH

Setup the Web Server (Nginx)

(Optional) Setup SSL

Add Subdomains