Procedure: Ubuntu 20.04 set up WireGuard VPN server

Our sample setup includes a simple peer connection between a cloud server running Ubuntu 20.04 LTS server, and a Ubuntu/Ubuntu/RHEL/SUSE/OpenSUSECentOS Linux desktop client:

The steps are as follows for installing and configuring WireGuard on Ubuntu Linux 20.04 LTS as a VPN server.

Please note that {vivek@ln-sg-vpn-001:~ }$ OR {vivek@ubuntu-20-4-vpn-client:~ }$ is my shell prompt and is not part of actual commands. In other words, you need to copy and paste command after my shell prompt.

Step 1 – Update your system

Run the apt command to install Ubuntu 20.04 security updates:
{vivek@ln-sg-vpn-001:~ }$ sudo apt update
{vivek@ln-sg-vpn-001:~ }$ sudo apt upgrade

Step 2 – Installing a WireGuard VPN server on Ubuntu 20.04 LTS

Now we got our server updates with the latest security patches. It is time for setting up a WireGuard VPN server on Ubuntu 20.04 server. Enter:
{vivek@ln-sg-vpn-001:~ }$ sudo apt install wireguard

Step 3 – Configuring WireGuard server

First we need to create a private and public key pair for the WireGuard server. Let us cd into /etc/wireguard using the cd command
{vivek@ln-sg-vpn-001:~ }$ sudo -i
{root@ln-sg-vpn-001:~ }# cd /etc/wireguard/
Execute the following command:
{vivek@ln-sg-vpn-001:~ }# umask 077; wg genkey | tee privatekey | wg pubkey > publickey
To view keys created use the cat command and ls command:
{vivek@ln-sg-vpn-001:~ }# ls -l privatekey publickey
{vivek@ln-sg-vpn-001:~ }# cat privatekey
## Please note down the private key ##
{vivek@ln-sg-vpn-001:~ }# cat publickey

Set Up WireGuard VPN on Ubuntu by Editing wg0.conf

Edit or update the /etc/wireguard/wg0.conf file as follows:
{vivek@ln-sg-vpn-001:~ }$ sudo nano /etc/wireguard/wg0.conf
## OR ##
{vivek@ln-sg-vpn-001:~ }$ sudo vim /etc/wireguard/wg0.conf
Append the following config directives:

## Set Up WireGuard VPN on Ubuntu By Editing/Creating wg0.conf File ##
[Interface]
## My VPN server private IP address ##
Address = 192.168.6.1/24
 
## My VPN server port ##
ListenPort = 41194
 
## VPN server's private key i.e. /etc/wireguard/privatekey ##
PrivateKey = eEvqkSJVw/7cGUEcJXmeHiNFDLBGOz8GpScshecvNHU=
 
## Save and update this config file when a new peer (vpn client) added ##
SaveConfig = true

Save and close the file when using vim text editor.

Step 4 – Set up UFW firewall rules

I am assuming that you have UFW configured and we are going to open UDP 41194 port using the ufw command as follows:
sudo ufw allow 41194/udp
See “How To Configure Firewall with UFW on Ubuntu 20.04 LTS” for more info.

Step 5 – Enable and start WireGuard service

Turn the WireGuard service at boot time using the systemctl command, run:
{vivek@ln-sg-vpn-001:~ }$ sudo systemctl enable wg-quick@wg0
Start the service, execute:
{vivek@ln-sg-vpn-001:~ }$ sudo systemctl start wg-quick@wg0
Get the service status, run:
{vivek@ln-sg-vpn-001:~ }$ sudo systemctl status wg-quick@wg0

Verify that interface named wg0 is up and running on Ubuntu server using the ip command:
{vivek@ln-sg-vpn-001:~ }$ sudo wg
{vivek@ln-sg-vpn-001:~ }$ sudo ip a show wg0

Step 6 – Wireguard VPN client configuration

The procedure for installing and configuring a VPN client is the same as setting up the server. Let us install the client on an Ubuntu Linux 20.04 LTS desktop:
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo apt install wireguard
Next we need create VPN client config on Ubuntu/Debian/CentOS Linux destkop:
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo sh -c 'umask 077; touch /etc/wireguard/wg0.conf'
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo -i
{root@ubuntu-20-4-vpn-client:~ }# cd /etc/wireguard/
{root@ubuntu-20-4-vpn-client:~ }# umask 077; wg genkey | tee privatekey | wg pubkey > publickey
{root@ubuntu-20-4-vpn-client:~ }# ls -l publickey privatekey
## Note down the privatekey ##
{root@ubuntu-20-4-vpn-client:~ }# cat privatekey

Edit the /etc/wireguard/wg0.conf file:
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo nano /etc/wireguard/wg0.conf
## OR ##
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo vim /etc/wireguard/wg0.conf
Append the following directives:

[Interface]
## This Desktop/client's private key ##
PrivateKey = uJPzgCQ6WNlAUp3s5rabE/EVt1qYh3Ym01sx6oJI0V4=
 
## Client ip address ##
Address = 192.168.6.2/24
 
[Peer]
## Ubuntu 20.04 server public key ##
PublicKey = qdjdqh2+N3DEMDUDRob8K3b+9BZFJbT59f+rBrl99zM
 
## set ACL ##
AllowedIPs = 192.168.6.0/24
 
## Your Ubuntu 20.04 LTS server's public IPv4/IPv6 address and port ##
Endpoint = 172.105.112.120:41194
 
##  Key connection alive ##
PersistentKeepalive = 15

Enable and start VPN client/peer connection, run:
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo systemctl enable wg-quick@wg0
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo systemctl start wg-quick@wg0
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo systemctl status wg-quick@wg0

Allow desktop client and Ubuntu server connection over VPN

We need to configure the server-side peer-to-peer VPN option and allow a connection between the client computer and the server. Let us go back to our Ubuntu 20.04 LTS server and edit wg0.conf file to add [Peer] (client) information as follows (type commands on your server box):
{vivek@ln-sg-vpn-001:~ }$ sudo systemctl stop wg-quick@wg0
{vivek@ln-sg-vpn-001:~ }$ sudo vi /etc/wireguard/wg0.conf
Append the following config:

[Peer]
## Desktop/client VPN public key ##
PublicKey = u2ao8GNNUWAirtjq0eL1UpHVkMep5/EUalbZcdH0imc=
 
## client VPN IP address (note  the /32 subnet) ##
AllowedIPs = 192.168.6.2/32

Save and close the file. Next start the service again, run:
{vivek@ln-sg-vpn-001:~ }$ sudo systemctl start wg-quick@wg0

Step 7 – Verification

That is all, folks. By now, both Ubuntu servers and clients must be connected securely using a peer-to-peer VPN called WireGuard. Let us test the connection. Type the following ping command on your client machine/desktop system:
{vivek@ubuntu-20-4-vpn-client:~ }$ ping -c 4 192.168.6.1
{vivek@ubuntu-20-4-vpn-client:~ }$ sudo wg

Step 8 – Firewall configurations

Now we have set up and configured peer-to-peer VPN networking for our Ubuntu server and client. However, you may want to give access to the Internet for all VPN clients. For these purposes, we need to set up IPv4 and IPv6 firewall rules, including NAT and IP forwarding. See the following tutorial:

• How To Set Up WireGuard Firewall Rules in Linux

Conclusion

Congratulation! You just learned about setting up a WireGuard VPN server on Ubuntu 20.04 LTS server and peer (client machine) on both Ubuntu/CentOS Linux desktop. I strongly suggest that you read WireGuard project documentation here.