Ubuntu Server Setup

All the steps required to build an Ubuntu app server with SSH, Firewall, Nginx, SSL, Node, Postgres

Note: we will be using new user 'ifactory' to make it easier to copy and paste commands

1. Pre-Steps

1. Have a a PuttyGen Public .pub (uploaded to Ubuntu server) and Private.ppk (stored on your PC) SSH key setup.

2. Deploy an Ubuntu server on AWS, Azure, Digital Ocean, Linode, OVH or Australian dedicated/VPS provider.

3. Basic understanding of the nano editor: https://www.nano-editor.org/dist/latest/cheatsheet.html

• CTRL-U paste

• CTRL-O to save

• CTRL-X to exit

• CTRL-Z to minmise Nano then 'fg' to re-maximise

1. SSH into server with the root user created by cloud provider.

2. Update Server

Update Ubuntu packages.

$ apt update             [ inform server about lastest updates available ]
$ apt list --upgradeable [ returns a list of upgradable packages. run after: $ apt update ]
$ apt upgrade            [ Install latest updates ]

3. Set Server Hostname, IP and Domain

https://www.linode.com/docs/guides/getting-started/

Set the server hostname - its just a generic handle and not a domain name

$ hostnamectl set-hostname example-hostname     [ set hostname ]
$ hostnamectl status                            [ Check hostname is updated ]
$ nano /etc/hosts                               [ Edit hosts file ]

Add line in Nano editor and add server public IP and domain name:

203.0.113.10 example-hostname.example.com example-hostname

4. Set Server Timezone

$ timedatectl                   [ Show timezone info ]
$ dpkg-reconfigure tzdata       [ Set the timezone interactively ]

5. Security

install Fail2ban to limit failed SSH requests:

$ apt install fail2ban
$ cd /etc/fail2ban
$ cp jail.conf jail.local       [ Create a copy of config file. this wil be read automatically on service restart ]
$ nano jail.local               [ Open file in Nano editor ]

Uncomment and add to ignoreip office IP address, ban time, max retry etc.

[Sshd] 
enabled=true 

Then write out file.

$ service fail2ban restart     [ Restart fail2ban for services to run. ] 

Install Fail2Ban: https://www.linode.com/docs/guides/using-fail2ban-to-secure-your-server-a-tutorial/

6. Unattended Upgrades

$ apt install unattended-upgrades                 [ Install ]
$ systemctl enable unattended-upgrades            [ Enable ]
$ systemctl start unattended-upgrades             [ Start ]
$ nano /etc/apt/apt.conf.d/50unattended-upgrades  [ Set what to upgrade ]
$ nano /etc/apt/apt.conf.d/20auto-upgrades        [ Set when to upgrade ]
$ sudo unattended-upgrades --dry-run --debug      [ Confirm config ]

https://www.linode.com/docs/guides/how-to-configure-automated-security-updates-ubuntu/

7. Setup Firewall

Turn on firewall and open to HTTP, HTTPS, OpenSSH

$ ufw allow OpenSSH     [ Enable firewall to accept firewall connections OpenSSH over port 22 ]
$ ufw allow http        [ Allow http over port 80 ]
$ ufw allow https       [ Allow https over port 443 ]
$ sudo ufw allow from 119.18.38.68 to any port 5432   [ Allow Postgres port 5432 from iFactory office ]
$ sudo ufw allow from 118.88.24.53 to any port 465    [ Allow nodemailer to receive response from external mail host ]
$ ufw enable            [ Enable firewall ]
$ sudo ufw disable      [ Disable firewall ]
$ sudo ufw reload       [ Reload firewall rules ]

Additonal commands

$ ufw status verbose          [ show current firewall ]
$ ufw deny   [ deny a particular service or port ]
$ ufw status numbered         [ show rules with a number - use number to delete a rule ]
$ ufw delete          [ delete a port or service by its status rule number ]

https://www.digitalocean.com/community/tutorials/ufw-essentials-common-firewall-rules-and-commands

https://www.digitalocean.com/community/tutorials/initial-server-setup-with-ubuntu-18-04

https://www.linode.com/docs/security/securing-your-server/

8. Setup Non-Root User

Setup a non Root user, grant Sudo and open firewall to OpenSSH

$ adduser ifactory              [ Create new user 'ifactory' ]
$ usermod -aG sudo ifactory     [ Grant new user Sudo permssions ]

Related Commands:

$ less /etc/group               [ list all Ubuntu groups ]
  'q' to exit list
$ passwd ifactory               [ Set/change password for user 'ifactory' ]
$ groups ifactory               [ Show if a user exists and its groups e.g. sudo ssl-cert  ]
$ getent passwd | grep ifactory [ Search for a user ] 

9. Add New Users SSH Key

Requires you have already created an ssh-rsa Public privata key pair using PuttyGen.

$ cd /home/ifactory
$ mkdir .ssh
$ touch .ssh/authorized_keys
$ nano .ssh/authorized_keys

https://www.digitalocean.com/community/questions/ubuntu-16-04-creating-new-user-and-adding-ssh-keys

10. Set Permissions on New User Home directory

$ chown -R ifactory:ifactory /home/ifactory/
$ chmod 700 /home/ifactory/.ssh
$ chmod 644 /home/ifactory/.ssh/authorized_keys

11. Setup Visual Studio Code SSH Access

Visual Studio Code (VS Code) can work off a remote development server with these steps:

1. In VS Code, install the Microsoft extension 'Remote - SSH'

2. If your SSH server access is with a PuttyGen .ppk key, you may need to convert to the OpenSSH fromat:

• Open PuttyGen.

• Load the .ppk key using 'Load' button.

• Select from top navigation > Conversions > Export OpneSSH key ( force new file format ).

• When prompted save file: my-ssh-key.open-ssh.ppk to differetiate from existing standard my-ssh-key.ppk.

1. In VS Code select the 'Remote Explorer' icon in side navigation and select '+' to add a new SSH target.

12. Disable SSH Password Authentication - OPTIONAL

It is safer to only allow SSH conections via a key and not a password. Before disabling password authentication, make sure that you either have SSH key-based authentication configured for the root account on this server, or preferably, that you have SSH key-based authentication configured for an account on this server with sudo access.

https://www.digitalocean.com/community/tutorials/how-to-configure-ssh-key-based-authentication-on-a-linux-server