setup-ipsec-vpn/README.md

IPsec VPN Server Auto Setup Scripts

Set up your own IPsec VPN server in just a few minutes, with both IPsec/L2TP and Cisco IPsec on Ubuntu, Debian and CentOS. All you need to do is provide your own VPN credentials, and let the scripts handle the rest.

An IPsec VPN encrypts your network traffic, so that nobody between you and the VPN server can eavesdrop on your data as it travels via the Internet. This is especially useful when using unsecured networks, e.g. at coffee shops, airports or hotel rooms.

We will use Libreswan as the IPsec server, and xl2tpd as the L2TP provider.

» See also: IPsec VPN Server on Docker

Read this in other languages: English, 简体中文.

Table of Contents

• Quick start
• Features
• Requirements
• Installation
• Next steps
• Important notes
• Upgrade Libreswan
• Bugs & Questions
• Uninstallation
• See also
• License

Quick start

First, prepare your Linux server* with a fresh install of Ubuntu LTS, Debian or CentOS.

Use this one-liner to set up an IPsec VPN server:

wget https://git.io/vpnsetup -O vpnsetup.sh && sudo sh vpnsetup.sh

If using CentOS, replace the link above with https://git.io/vpnsetup-centos.

Your VPN login details will be randomly generated, and displayed on the screen when finished.

For other installation options and how to set up VPN clients, read the sections below.

* A dedicated server or virtual private server (VPS). OpenVZ VPS is not supported.

Features

• New: The faster IPsec/XAuth ("Cisco IPsec") mode is supported
• New: A pre-built Docker image of the VPN server is now available
• Fully automated IPsec VPN server setup, no user input needed
• Encapsulates all VPN traffic in UDP - does not need ESP protocol
• Can be directly used as "user-data" for a new Amazon EC2 instance
• Includes sysctl.conf optimizations for improved performance
• Tested with Ubuntu 20.04/18.04/16.04, Debian 10/9/8 and CentOS 8/7/6

Requirements

A newly created Amazon EC2 instance, from one of these images:

• Ubuntu 20.04 (Focal), 18.04 (Bionic) or 16.04 (Xenial)
• Debian 10 (Buster)*, 9 (Stretch) or 8 (Jessie)
• CentOS 8 (x86_64) with Updates
• CentOS 7 (x86_64) with Updates
• CentOS 6 (x86_64) with Updates
• Red Hat Enterprise Linux (RHEL) 8, 7 or 6

Please see detailed instructions and EC2 pricing.

-OR-

A dedicated server or KVM/Xen-based virtual private server (VPS), freshly installed with one of the above OS. OpenVZ VPS is not supported, users could instead try OpenVPN.

This also includes Linux VMs in public clouds, such as DigitalOcean, Vultr, Linode, Google Compute Engine, Amazon Lightsail, Microsoft Azure, IBM Cloud, OVH and Rackspace.

» I want to run my own VPN but don't have a server for that

Advanced users can set up the VPN server on a $35 Raspberry Pi. See [1] [2].

* Debian 10 users should use the standard Linux kernel (not the "cloud" version). Read more here.

⚠️ DO NOT run these scripts on your PC or Mac! They should only be used on a server!

Installation

Ubuntu & Debian

First, update your system with apt-get update && apt-get dist-upgrade and reboot. This is optional, but recommended.

To install the VPN, please choose one of the following options:

Option 1: Have the script generate random VPN credentials for you (will be displayed when finished):

wget https://git.io/vpnsetup -O vpnsetup.sh && sudo sh vpnsetup.sh

Option 2: Edit the script and provide your own VPN credentials:

wget https://git.io/vpnsetup -O vpnsetup.sh
nano -w vpnsetup.sh
[Replace with your own values: YOUR_IPSEC_PSK, YOUR_USERNAME and YOUR_PASSWORD]
sudo sh vpnsetup.sh

Note: A secure IPsec PSK should consist of at least 20 random characters.

Option 3: Define your VPN credentials as environment variables:

# All values MUST be placed inside 'single quotes'
# DO NOT use these special characters within values: \ " '
wget https://git.io/vpnsetup -O vpnsetup.sh && sudo \
VPN_IPSEC_PSK='your_ipsec_pre_shared_key' \
VPN_USER='your_vpn_username' \
VPN_PASSWORD='your_vpn_password' \
sh vpnsetup.sh

Note: If unable to download via wget, you may also open vpnsetup.sh (or vpnsetup_centos.sh) and click the Raw button. Press Ctrl-A to select all, Ctrl-C to copy, then paste into your favorite editor.

CentOS & RHEL

First, update your system with yum update and reboot. This is optional, but recommended.

Follow the same steps as above, but replace https://git.io/vpnsetup with https://git.io/vpnsetup-centos.

Next steps

Get your computer or device to use the VPN. Please refer to:

Configure IPsec/L2TP VPN Clients

Configure IPsec/XAuth ("Cisco IPsec") VPN Clients

Step-by-Step Guide: How to Set Up IKEv2 VPN

If you get an error when trying to connect, see Troubleshooting.

Enjoy your very own VPN! ✨🎉🚀✨

Important notes

Read this in other languages: English, 简体中文.

Windows users: This one-time registry change is required if the VPN server and/or client is behind NAT (e.g. home router).

Android users: If you encounter connection issues, try these steps.

The same VPN account can be used by your multiple devices. However, due to an IPsec/L2TP limitation, if you wish to connect multiple devices simultaneously from behind the same NAT (e.g. home router), you must use only IPsec/XAuth mode.

If you wish to add, edit or remove VPN user accounts, see Manage VPN Users. Helper scripts are included for convenience.

For servers with an external firewall (e.g. EC2/GCE), open UDP ports 500 and 4500 for the VPN. Aliyun users, see #433.

Clients are set to use Google Public DNS when the VPN is active. If another DNS provider is preferred, replace 8.8.8.8 and 8.8.4.4 in both /etc/ppp/options.xl2tpd and /etc/ipsec.conf, then reboot your server. Advanced users can define VPN_DNS_SRV1 and optionally VPN_DNS_SRV2 when running the VPN setup script.

Using kernel support could improve IPsec/L2TP performance. It is available on Ubuntu 16.04-20.04, Debian 9-10 and CentOS 6-8. Ubuntu users: Install linux-modules-extra-$(uname -r) (or linux-image-extra), then run service xl2tpd restart.

To modify the IPTables rules after install, edit /etc/iptables.rules and/or /etc/iptables/rules.v4 (Ubuntu/Debian), or /etc/sysconfig/iptables (CentOS/RHEL). Then reboot your server.

When connecting via IPsec/L2TP, the VPN server has IP 192.168.42.1 within the VPN subnet 192.168.42.0/24.

The scripts will backup existing config files before making changes, with .old-date-time suffix.

Upgrade Libreswan

The additional scripts vpnupgrade.sh and vpnupgrade_centos.sh can be used to upgrade Libreswan (changelog | announce). Edit the SWAN_VER variable as necessary. Check which version is installed: ipsec --version.

# Ubuntu & Debian
wget https://git.io/vpnupgrade -O vpnupgrade.sh
# CentOS & RHEL
wget https://git.io/vpnupgrade-centos -O vpnupgrade.sh

Bugs & Questions

• Got a question? Please first search other people's comments in this Gist and on my blog.
• Ask VPN related questions on the Libreswan or strongSwan mailing list, or read these wikis: [1] [2] [3] [4] [5].
• If you found a reproducible bug, open a GitHub Issue to submit a bug report.

Uninstallation

Please refer to Uninstall the VPN.

See also

• IPsec VPN Server on Docker
• Algo VPN
• Streisand
• OpenVPN Install

License

Copyright (C) 2014-2020 Lin Song
Based on the work of Thomas Sarlandie (Copyright 2012)

This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License
Attribution required: please include my name in any derivative and let me know how you have improved it!