Ubuntu 18.04 LTS Set Up OpenVPN Server In 5 Minutes

I am a new Ubuntu Linux 18.04 LTS server user. How do I set up an OpenVPN Server on Ubuntu Linux version 18.04 LTS server to shield my browsing activity from bad guys on public Wi-Fi, and more?

Introduction OpenVPN is a full-featured SSL VPN (virtual private network). It implements OSI layer 2 or 3 secure network extension using the SSL/TLS protocol. It is an open source software and distributed under the GNU GPL. A VPN allows you to connect securely to an insecure public network such as wifi network at the airport or hotel. VPN is also required to access your corporate or enterprise or home server resources. You can bypass the geo-blocked site and increase your privacy or safety online. This tutorial provides step-by-step instructions for configuring an OpenVPN server on Ubuntu Linux 18.04 LTS server.

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Procedure: Ubuntu 18.04 LTS Set Up OpenVPN Server In 5 Minutes

The steps are as follows:

Step 1 – Update your system

Run the apt command/apt-get command:
$ sudo apt update
$ sudo apt upgrade

Step 2 – Find and note down your IP address

Use the ip command as follows:
$ ip a
$ ip a show eth0

ip command get my IP address on Ubuntu Linux 18.04 LTS
Another option is to run the following dig command/host command to find out your public IP address from Linux command line:
$ dig +short myip.opendns.com @resolver1.opendns.com
OR
dig TXT +short o-o.myaddr.l.google.com @ns1.google.com | awk -F'"' '{ print $2}'
Find out my public IP address using the CLI

A note about IP address

Most cloud servers have two types of IP address:

  1. Public static IP address directly assigned to your box and routed from the Internet. For example, Linode, Digital Ocean, and others gives you direct public IP address.
  2. Private static IP address directly attached to your server and your server is behind NAT with public IP address. For example, AWS EC2/Lightsail give you this kind of NAT public IP address.

The script will automatically detect your networking setup. All you have to do is provide correct IP address when asked for it.

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

I am going to use the wget command:
$ wget https://git.io/vpn -O openvpn-install.sh
Download openvpn-install.sh script to setup OpenVPN server in 5 minutes on Ubuntu
Setup permissions using the chmod command:
$ chmod +x openvpn-install.sh
One can view the script using a text editor such as nano/vim:
$ vim openvpn-install.sh

Run openvpn-install.sh to install OpenVPN server

Now all you have to do is:
$ 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?

We need to use the systemctl command:
$ sudo systemctl stop openvpn-server@server.service # <--- stop server
$ sudo systemctl start openvpn-server@server.service # <--- start server
$ sudo systemctl restart openvpn-server@server.service # <--- restart server
$ sudo systemctl status openvpn-server@server.service # <--- get server status

 openvpn@server.service - OpenVPN connection to server
     Loaded: loaded (/etc/systemd/system/openvpn@.service; enabled; vendor preset: enabled)
     Active: active (running) since Sat 2020-08-08 04:12:49 UTC; 1 weeks 0 days ago
       Docs: man:openvpn(8)
             https://community.openvpn.net/openvpn/wiki/Openvpn24ManPage
             https://community.openvpn.net/openvpn/wiki/HOWTO
   Main PID: 2344 (openvpn)
     Status: "Initialization Sequence Completed"
      Tasks: 1 (limit: 2282)
     Memory: 1.7M
     CGroup: /system.slice/system-openvpn.slice/openvpn@server.service
             └─2344 /usr/sbin/openvpn --daemon ovpn-server --status /run/openvpn/server.status 10 --cd /etc/openvpn --script-security 2 --config /etc/openvpn/server.conf --writepid /run/openvpn/server.pid

Aug 15 08:11:12 sg-vpn-1 ovpn-server[2344]: 13.x.yyy.zzz:47582 peer info: IV_TCPNL=1
Aug 15 08:11:12 sg-vpn-1 ovpn-server[2344]: 13.x.yyy.zzz:47582 Control Channel: TLSv1.3, cipher TLSv1.3 TLS_AES_256_GCM_SHA384, 256 bit EC, curve: prime256v1
Aug 15 08:11:12 sg-vpn-1 ovpn-server[2344]: 13.x.yyy.zzz:47582 [LinuxDesktopSG1] Peer Connection Initiated with [AF_INET]13.x.yyy.zzz:47582
Aug 15 08:11:12 sg-vpn-1 ovpn-server[2344]: LinuxDesktopSG1/13.x.yyy.zzz:47582 MULTI_sva: pool returned IPv4=10.8.0.3, IPv6=(Not enabled)
Aug 15 08:11:12 sg-vpn-1 ovpn-server[2344]: LinuxDesktopSG1/13.x.yyy.zzz:47582 MULTI: Learn: 10.8.0.3 -> LinuxDesktopSG1/13.x.yyy.zzz:47582
Aug 15 08:11:12 sg-vpn-1 ovpn-server[2344]: LinuxDesktopSG1/13.x.yyy.zzz:47582 MULTI: primary virtual IP for LinuxDesktopSG1/13.x.yyy.zzz:47582: 10.8.0.3
Aug 15 08:11:13 sg-vpn-1 ovpn-server[2344]: LinuxDesktopSG1/13.x.yyy.zzz:47582 PUSH: Received control message: 'PUSH_REQUEST'
Aug 15 08:11:13 sg-vpn-1 ovpn-server[2344]: LinuxDesktopSG1/13.x.yyy.zzz:47582 SENT CONTROL [LinuxDesktopSG1]: 'PUSH_REPLY,dhcp-option DNS 10.8.0.1,redirect-gateway def1 bypass-dhcp,route-gateway 10.8.0.1,topology subnet,pin>
Aug 15 08:11:13 sg-vpn-1 ovpn-server[2344]: LinuxDesktopSG1/13.x.yyy.zzz:47582 Outgoing Data Channel: Cipher 'AES-128-GCM' initialized with 128 bit key
Aug 15 08:11:13 sg-vpn-1 ovpn-server[2344]: LinuxDesktopSG1/13.x.yyy.zzz:47582 Incoming Data Channel: Cipher 'AES-128-GCM' initialized with 128 bit key

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:

  1. Apple iOS client
  2. Android client
  3. Apple MacOS (OS X) client
  4. 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

Step 6 - Adding or removing OpenVPN client

Log in to your server and run the script again:
$ sudo ./openvpn-install.sh

OpenVPN is already installed.

Select an option:
   1) Add a new client
   2) Revoke an existing client
   3) Remove OpenVPN
   4) Exit
Option: 

Use option number 1 to add a new client and option number 2 to remove or revoke an existing OpenVPN client from the server.

A note about trouble shooting OpenVPN server and client issues

Check OpenVPN server for errors using the jourlctl command:
$ sudo journalctl --identifier openvpn
## OR filter it using the grep command/egrep command
$ sudo journalctl -x -e | grep -i 'error'
$ sudo journalctl -x -e | egrep -i 'error|warn|your_ip_here'
$ sudo journalctl -xe -u openvpn-server@server.service

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/systemd/system/openvpn-iptables.service

[Unit]
Before=network.target
[Service]
Type=oneshot
ExecStart=/sbin/iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to 172.xxx.yyy.zzz
ExecStart=/sbin/iptables -I INPUT -p udp --dport 1194 -j ACCEPT
ExecStart=/sbin/iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT
ExecStart=/sbin/iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
ExecStop=/sbin/iptables -t nat -D POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to 172.xxx.yyy.zzz
ExecStop=/sbin/iptables -D INPUT -p udp --dport 1194 -j ACCEPT
ExecStop=/sbin/iptables -D FORWARD -s 10.8.0.0/24 -j ACCEPT
ExecStop=/sbin/iptables -D FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
ExecStart=/sbin/ip6tables -t nat -A POSTROUTING -s fddd:1194:1194:1194::/64 ! -d fddd:1194:1194:1194::/64 -j SNAT --to 2600:xxxx::yyyy:zzzz:dddd:cccc
ExecStart=/sbin/ip6tables -I FORWARD -s fddd:1194:1194:1194::/64 -j ACCEPT
ExecStart=/sbin/ip6tables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
ExecStop=/sbin/ip6tables -t nat -D POSTROUTING -s fddd:1194:1194:1194::/64 ! -d fddd:1194:1194:1194::/64 -j SNAT --to 2600:xxxx::yyyy:zzzz:dddd:cccc
ExecStop=/sbin/ip6tables -D FORWARD -s fddd:1194:1194:1194::/64 -j ACCEPT
ExecStop=/sbin/ip6tables -D FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
RemainAfterExit=yes
[Install]
WantedBy=multi-user.target

Of course, we check status of the iptables rules that required for OpenVPN using the following command:
$ sudo systemctl status openvpn-iptables.service
If not running or failed start it:
$ sudo systemctl start openvpn-iptables.service
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 systemctl start openvpn-iptables.service
$ 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 server, Github script page, and Ubuntu server/project for additional information.

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17 comments… add one
  • nas Aug 9, 2020 @ 15:18

    it doesn’t work

  • Gangasagar Aug 12, 2020 @ 12:14

    how to connect openvpn from web by installing above method

    • 🐧 Vivek Gite Aug 15, 2020 @ 8:57

      Once server configured, download clients as per your operating system. Copy the client file (.ovpn) from the server and install it using your client app.

  • ignacio Aug 14, 2020 @ 16:25

    when i try to start server it gives me the following error:

    Job for openvpn@server.service failed because the control process exited with error code.
    See “systemctl status openvpn@server.service” and “journalctl -xe” for details.

    • 🐧 Vivek Gite Aug 15, 2020 @ 8:22

      Check status and error log using the following syntax (note the correct name of service changed/updated in scripts to ‘openvpn-server@server.service‘:
      sudo systemctl status openvpn-server@server.service
      sudo journalctl -xe -u openvpn-server@server.service
      sudo journalctl -xe | more

  • Hannah Aug 17, 2020 @ 14:30

    This worked perfectly on a fresh install of 18.04. Thank you. Is there a way more suited to this install script to create a second client?

    • 🐧 Vivek Gite Aug 17, 2020 @ 17:17

      Run the same script again to add or remove client.

  • Ram.k Aug 27, 2020 @ 19:58

    Great post… it worked for me… please include how to add authentication for the openvpn clients.

  • Phan Loi Sep 1, 2020 @ 8:19

    Great post. It work perfectly for me.

    Is there any way we can enable both IPv4 and IPv6? When I try this, only my IPv4 get change. My IPv6 is not changed.

    • 🐧 Vivek Gite Sep 13, 2020 @ 6:59

      You need to specify IPv6 while setting up server.

  • Jerry Sep 13, 2020 @ 3:46

    I get the following:

    Sep 12 22:36:01 nvr ovpn-server[31205]: Options error: In [CMD-LINE]:1: Error opening configuration file: /etc/openvpn/server.conf
    Sep 12 22:36:01 nvr ovpn-server[31205]: Use --help for more information.
    Sep 12 22:36:01 nvr systemd[1]: openvpn@server.service: Main process exited, code=exited, status=1/FAILURE

    The file is there, just not sure why it can’t open it.

  • lumajang Sep 24, 2020 @ 3:28

    is this can only connect to 1 device? because when i try with laptop and android one of them disconnected

    • 🐧 Vivek Gite Sep 24, 2020 @ 7:33

      You need to create user/certificate for each device. See step # 6.

  • lumajang Sep 24, 2020 @ 3:29

    is this can only connect to 1 device? when i connect with 2 device 1 get disconnected

  • chico1852 Sep 27, 2020 @ 10:59

    Impossible to download deskcop.ovpn:
    ssh: connect to host 104.20.187.5 port 22: Connection timed out

  • Anonymous Oct 13, 2020 @ 19:53

    Dear, i can’t connect, i think it is because of DPI of my internet provider.
    Can you tell me which tls version used this server configuration, is it tls 1.3???

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