How to Set Up an L2TP/IPsec VPN Server on Linux

1) Install the DKMS package

Add VPN on client computer (Mac)
The scenario There are two offices. Now, we can use the variables we set and the easy-rsa utilities to build our certificate authority. Next, we will generate our server certificate and key pair, as well as some additional files used during the encryption process. I don't want to spent too many hours setting it up. The traffic emerges from the VPN server and continues its journey to the destination. When installing Openswan, you will be asked whether you want to create an X.

Enable IP Forwarding

Set up a Linux VPN server by following these 10 steps

Nano is a text editor in the terminal. If the file is located somewhere else on your machine google or look for it. Your internet may temporarily stop working at this point! That line means it will use the first address, then the second if the first one fails, and finally 8. This usually will not happen. Now save and exit as shown below:. This will save and close the file. You should now check to see if it works. Enter the command below, and see if the nameservers show up.

Do a DNS leak test on the website linked above. Fixing a DNS leak in web browser: The Miscellaneous Tab is our final tab. We shouldn't have anything to do here. The default setup should work just fine in many cases.

We now click the Addbutton and highlight our new connection and choose Start. We have now created a VPN connection to a remote host! Congratulations for using Linux and sticking with a slightly frustrating task. If you have any questions or comments please drop me a line at jmgarvin itttech. Can Russian hackers be stopped?

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My Profile Log Out. Below this, add the key-direction parameter set to "0":. Next, find the section on cryptographic ciphers by looking for the commented out cipher lines. Below this, add an auth line to select the HMAC message digest algorithm. For this, SHA is a good choice:.

Finally, find the user and group settings and remove the " ; " at the beginning of to uncomment those lines:. The settings above will create the VPN connection between the two machines, but will not force any connections to use the tunnel. If you wish to use the VPN to route all of your traffic, you will likely want to push the DNS settings to the client computers.

You can do this, uncomment a few directives that will configure client machines to redirect all web traffic through the VPN. Find the redirect-gateway section and remove the semicolon " ; " from the beginning of the redirect-gateway line to uncomment it:.

Just below this, find the dhcp-option section. Again, remove the " ; " from in front of both of the lines to uncomment them:. If you need to use a different port because of restrictive network environments that your clients might be in, you can change the port option.

If you are not hosting web content your OpenVPN server, port is a popular choice since this is usually allowed through firewall rules. Often if the protocol will be restricted to that port as well. If you have no need to use a different port, it is best to leave these two settings as their default.

If you selected a different name during the. If you used the default server , this should already be set correctly:. Next, we need to adjust some aspects of the server's networking so that OpenVPN can correctly route traffic. First, we need to allow the server to forward traffic.

This is fairly essential to the functionality we want our VPN server to provide. Inside, look for the line that sets net. Remove the " " character from the beginning of the line to uncomment that setting:.

If you followed the Ubuntu Regardless of whether you use the firewall to block unwanted traffic which you almost always should do , we need the firewall in this guide to manipulate some of the traffic coming into the server. We need to modify the rules file to set up masquerading, an iptables concept that provides on-the-fly dynamic NAT to correctly route client connections. Before we open the firewall configuration file to add masquerading, we need to find the public network interface of our machine.

To do this, type:. Your public interface should follow the word "dev". For example, this result shows the interface named wlp11s0 , which is highlighted below:. This file handles configuration that should be put into place before the conventional UFW rules are loaded.

Towards the top of the file, add the highlighted lines below. We need to tell UFW to allow forwarded packets by default as well. We'll also add the SSH port in case you forgot to add it when following the prerequisite tutorial:.

We need to start the OpenVPN server by specifying our configuration file name as an instance variable after the systemd unit file name. Since our client configuration files will have the client keys embedded, we should lock down permissions on our inner directory:. Next, let's copy an example client configuration into our directory to use as our base configuration:. First, locate the remote directive. This points the client to our OpenVPN server address.

If you changed the port that the OpenVPN server is listening on, change to the port you selected:. Next, uncomment the user and group directives by removing the " ; ":. Find the directives that set the ca , cert , and key. Comment out these directives since we will be adding the certs and keys within the file itself:.

Next, add the key-direction directive somewhere in the file. This must be set to "1" to work with the server:. Finally, add a few commented out lines.

This script uses the resolvconf utility to update DNS information for Linux clients. Next, we will create a simple script to compile our base configuration with the relevant certificate, key, and encryption files. If you followed along with the guide, you created a client certificate and key called client1. If everything went well, we should have a client1.

We need to transfer the client configuration file to the relevant device. For instance, this could be your local computer or a mobile device. While the exact applications used to accomplish this transfer will depend on your choice and device's operating system, you want the application to use SFTP SSH file transfer protocol or SCP Secure Copy on the backend.

This will transport your client's VPN authentication files over an encrypted connection. Here is an example SFTP command using our client1. This command can be run from your local computer OS X or Linux. Here are several tools and tutorials for securely transferring files from the server to a local computer:.

None of these client instructions are dependent on one another, so feel free to skip to whichever is applicable to you. The OpenVPN connection will be called whatever you named the. In our example, this means that the connection will be called client1.

Server Setup