Wireguard on Linux : A basic approach using Ubuntu 20.04 LTS server and client

 We begin with a fresh installation of Ubuntu server 20.04 LTS

Server

1. Install wireguard
• sudo apt install wireguard
2. Generate server and client keys
• umask 077
• wg genkey | tee server_private_key | wg pubkey > server_public_key
• wg genkey | tee client_private_key | wg pubkey > client_public_key
3. Create server config
• Create a file wg0.conf in /etc/wireguard/
• [Interface] Address = 10.199.0.1/24 SaveConfig = true PrivateKey = <insert server_private_key> ListenPort = 51820 [Peer] PublicKey = <insert client_public_key> AllowedIPs = 10.199.0.2/24 <-- it means 254 IPs allowed to connect
• Note: If you only want 1 IP to connect,change /24 to /3You can change filename from wg0.conf to vpn.conf or whatever name you want
4. Running the wireguard's service
• sudo systemctl enable wg-quick@wg0 <-- need to run for the first time only
• sudo systemctl start wg-quick@wg0
5. Enable IP forwarding (Applicable for internet-enabled vpn connection. See client's note below)
• echo 1 > /proc/sys/net/ipv4/ip_forward
• sudo sysctl -p <-- to make the above change effective without reboot

Client

1. Install wireguard package
• sudo apt install wireguard
2. Create a file in /etc/wireguard called wg0.conf
• [Interface] Address = 10.199.0.2/24 PrivateKey = <insert client_private_key> DNS = 1.1.1.1 [Peer] PublicKey = <insert server_public_key> Endpoint = <insert vpn_server_address>:51820 AllowedIPs = 10.199.0.0/24 PersistentKeepalive = 60
• Note: Address parameter is the IP address for the client
• you can also change the name of the file wg0.conf to something else
• EndPoint is the wireguard server's IP address above.You can use IP or domain name
• DNS is the IP of DNS server for the client.
• *IF* the AllowedIPs is 0.0.0.0/0, it means all the traffic from the client
• will go through vpn server and if you want the client to be able to go to
• the internet, you must add this rule in the server:
• iptables -t nat -A POSTROUTING -s 10.199.0.0/24 -o eth0 -j MASQUERADE or
• You can put the iptables command above in server's wireguard config as below under [Interface]:
• PostUp = iptables -t nat -A POSTROUTING -s 10.199.0.0/24 -o eth0 -j MASQUERADE 
3. Connect the client
• sudo systemctl enable wg-quick@wg0 <-- run only this time
• sudo systemctl start wg-quick@wg0
• Test the connection: ping 10.199.0.1

That'sall there is to it. Hope it is working for you.

Cheers!

PS: Check this out! Easy setup for wireguard : https://github.com/burghardt/easy-wg-quick