OpenVPN: Instalasi di Ubuntu 18.04

Sumber: https://www.cyberciti.biz/faq/ubuntu-18-04-lts-set-up-openvpn-server-in-5-minutes/

Step 1 – Update system

Run,

sudo apt update
sudo apt upgrade

Step 2 – Cek IP address

Pakai perintah,

ip a
ip a show eth0
ip a show enp0s3

Step 3 – Download & run openvpn-install.sh script

Download,

sudo su
cd /usr/local/src/
wget https://git.io/vpn -O openvpn-install.sh
chmod +x openvpn-install.sh

Run,

sudo ./openvpn-install.sh

Sample session from AWS/Lightsail where my cloud server is behind NAT: Ubuntu 18.04 LTS Setup OpenVPN Server In 5 Minutes Sample session from Linode/DO server where cloud server has direct public IPv4 address: How To Setup OpenVPN Server In 5 Minutes on Ubuntu Linux To avoid problem always choose DNS as 1.1.1.1 or Google DNS. Those are fast DNS server and reached from anywhere on the Internet. How do I start/stop/restart OpenVPN server on Ubuntu 18.04 LTS?

sudo systemctl stop openvpn@server # <--- stop server
sudo systemctl start openvpn@server # <--- start server
sudo systemctl restart openvpn@server # <--- restart server
sudo systemctl status openvpn@server # <--- get server status

Step 4 – Connect an OpenVPN server using IOS/Android/Linux/Windows client

On server your will find a client configuration file called ~/desktop.ovpn. All you have to do is copy this file to your local desktop using the scp command:

$ scp vivek@104.20.187.5:~/deskcop.ovpn .

Next, provide this file to your OpenVPN client to connect:

   Apple iOS client
   Android client
   Apple MacOS (OS X) client
   Windows 8/10 client

Linux Desktop: OpenVPN client configuration

First, install the openvpn client for your desktop, enter: $ sudo yum install openvpn

OR

$ sudo apt install openvpn

Next, copy desktop.ovpn as follows:

$ sudo cp desktop.ovpn /etc/openvpn/client.conf

Test connectivity from the CLI:

$ sudo openvpn --client --config /etc/openvpn/desktop.conf

Your Linux system will automatically connect when computer restart using openvpn script/service:

$ sudo systemctl start openvpn@client # <--- start client service

Step 5 - Verify/test the connectivity

Execute the following commands after connecting to OpenVPN server from your Linux desktop:

$ ping 10.8.0.1 #Ping to the OpenVPN server gateway
$ ip route #Make sure routing setup working
$ dig TXT +short o-o.myaddr.l.google.com @ns1.google.com #Must return public IP address of OpenVPN server

A note about trouble shooting OpenVPN server and client issues

Check OpenVPN server for errors: $ journalctl --identifier ovpn-server

OpenVPN server log files and error Click to enlarge image

Is firewall rule setup correctly on your server? Use the cat command to see rules:

$ cat /etc/rc.local

#!/bin/sh -e
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to 172.26.6.74
exit 0

Another option is to run iptables command and sysctl command commands to verify NAT rule setup on your server:

$ sudo iptables -t nat -L -n -v
$ sysctl net.ipv4.ip_forward

NAT Firewall OpenVPN Rules Verification Insert the rules if not inserted from /etc/rc.local

$ sudo sh /etc/rc.local
$ sudo sysctl -w net.ipv4.ip_forward=1

Is OpenVPN server running and port is open? Use the ss command or netstat command and pidof command/ps command:

$ netstat -tulpn | grep :1194 ## 1194 is the openvpn server port ##
$ ss -tulpn | grep :1194 ## 1194 is the openvpn server port ##
$ ps aux | grep openvpn ## is the openvpn server running? ##
$ ps -C openvpn ## is the openvpn server running? ##
$ pidof openvpn ## find the openvpn server PID ##

Verify that OpenVPN server runnign and Port is Open on ubuntu Linux If not running, restart the OpenVPN server:

$ sudo systemctl restart openvpn@server

Look out for errors:

$ sudo systemctl status openvpn@server

Can the Linux desktop client connect to the OpenVPN server machine? First you need to run a simple test to see if the OpenVPN server port (UDP 1194) accepts connections:

$ nc -vu 104.20.187.5 1194

Connection to 104.20.187.5 1194 port [udp/openvpn] succeeded!

If not connected it means either a Linux desktop firewall or your router is blocking access to server. Make sure both client and server using same protocol and port, e.g. UDP port 1194.

Conclusion

Congratulations. You successfully set up an OpenVPN server on Ubuntu Linux 18.04 LTS server running in the cloud. See the OpenVPN website here and Ubuntu page here for additional information.

Referensi

• https://www.cyberciti.biz/faq/ubuntu-18-04-lts-set-up-openvpn-server-in-5-minutes/