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|openvpn-install.sh||8 months ago|
OpenVPN installer for Debian, Ubuntu, Fedora, CentOS, Arch Linux, Oracle Linux, Rocky Linux and AlmaLinux.
This script will let you setup your own secure VPN server in just a few seconds.
You can also check out wireguard-install, a simple installer for a simpler, safer, faster and more modern VPN protocol.
First, get the script and make it executable:
curl -O https://raw.githubusercontent.com/angristan/openvpn-install/master/openvpn-install.sh chmod +x openvpn-install.sh
Then run it:
You need to run the script as root and have the TUN module enabled.
The first time you run it, you'll have to follow the assistant and answer a few questions to setup your VPN server.
When OpenVPN is installed, you can run the script again, and you will get the choice to:
In your home directory, you will have
.ovpn files. These are the client configuration files. Download them from your server and connect using your favorite OpenVPN client.
If you have any question, head to the FAQ first. Please read everything before opening an issue.
PLEASE do not send me emails or private messages asking for help. The only place to get help is the issues. Other people may be able to help and in the future, other users may also run into the same issue as you. My time is not available for free just for you, you're not special.
It's also possible to run the script headless, e.g. without waiting for user input, in an automated manner.
AUTO_INSTALL=y ./openvpn-install.sh # or export AUTO_INSTALL=y ./openvpn-install.sh
A default set of variables will then be set, by passing the need for user input.
If you want to customise your installation, you can export them or specify them on the same line, as shown above.
If the server is behind NAT, you can specify its endpoint with the
ENDPOINT variable. If the endpoint is the public IP address which it is behind, you can use
ENDPOINT=$(curl -4 ifconfig.co) (the script will default to this). The endpoint can be an IPv4 or a domain.
Other variables can be set depending on your choice (encryption, compression). You can search for them in the
installQuestions() function of the script.
Password-protected clients are not supported by the headless installation method since user input is expected by Easy-RSA.
The headless install is more-or-less idempotent, in that it has been made safe to run multiple times with the same parameters, e.g. by a state provisioner like Ansible/Terraform/Salt/Chef/Puppet. It will only install and regenerate the Easy-RSA PKI if it doesn't already exist, and it will only install OpenVPN and other upstream dependencies if OpenVPN isn't already installed. It will recreate all local config and re-generate the client file on each headless run.
It's also possible to automate the addition of a new user. Here, the key is to provide the (string) value of the
MENU_OPTION variable along with the remaining mandatory variables before invoking the script.
The following Bash script adds a new user
foo to an existing OpenVPN configuration
#!/bin/bash export MENU_OPTION="1" export CLIENT="foo" export PASS="1" ./openvpn-install.sh
The script supports these Linux distributions:
|Amazon Linux 2||✅|
|CentOS 7||✅ 🤖|
|CentOS Stream >= 8||✅ 🤖|
|Debian >= 10||✅ 🤖|
|Fedora >= 35||✅ 🤖|
|Oracle Linux 8||✅|
|Rocky Linux 8||✅|
|Ubuntu >= 18.04||✅ 🤖|
To be noted:
This script is based on the great work of Nyr and its contributors.
Since 2016, the two scripts have diverged and are not alike anymore, especially under the hood. The main goal of the script was enhanced security. But since then, the script has been completely rewritten and a lot a features have been added. The script is only compatible with recent distributions though, so if you need to use a very old server or client, I advise using Nyr's script.
More Q&A in FAQ.md.
Q: Which provider do you recommend?
A: I recommend these:
Q: Which OpenVPN client do you recommend?
A: If possible, an official OpenVPN 2.4 client.
openvpnpackage from your distribution. There is an official APT repository for Debian/Ubuntu based distributions.
Q: Am I safe from the NSA by using your script?
A: Please review your threat models. Even if this script has security in mind and uses state-of-the-art encryption, you shouldn't be using a VPN if you want to hide from the NSA.
Q: Is there an OpenVPN documentation?
A: Yes, please head to the OpenVPN Manual, which references all the options.
More Q&A in FAQ.md.
Solutions that provision a ready to use OpenVPN server based on this script in one go are available for:
Please open an issue before submitting a PR if you want to discuss a change, especially if it's a big one.
Warning This has not been updated for OpenVPN 2.5 and later.
OpenVPN's default settings are pretty weak regarding encryption. This script aims to improve that.
OpenVPN 2.4 was a great update regarding encryption. It added support for ECDSA, ECDH, AES GCM, NCP and tls-crypt.
If you want more information about an option mentioned below, head to the OpenVPN manual. It is very complete.
By default, OpenVPN doesn't enable compression. This script provides support for LZ0 and LZ4 (v1/v2) algorithms, the latter being more efficient.
However, it is discouraged to use compression since the VORACLE attack makes use of it.
OpenVPN accepts TLS 1.0 by default, which is nearly 20 years old.
tls-version-min 1.2 we enforce TLS 1.2, which the best protocol available currently for OpenVPN.
TLS 1.2 is supported since OpenVPN 2.3.3.
OpenVPN uses an RSA certificate with a 2048 bits key by default.
OpenVPN 2.4 added support for ECDSA. Elliptic curve cryptography is faster, lighter and more secure.
This script provides:
It defaults to ECDSA with
SHA-256 as the signature hash by default, and so does the script. It provides no other choice as of now.
By default, OpenVPN uses
BF-CBC as the data channel cipher. Blowfish is an old (1993) and weak algorithm. Even the official OpenVPN documentation admits it.
The default is BF-CBC, an abbreviation for Blowfish in Cipher Block Chaining mode.
Using BF-CBC is no longer recommended, because of its 64-bit block size. This small block size allows attacks based on collisions, as demonstrated by SWEET32. See https://community.openvpn.net/openvpn/wiki/SWEET32 for details. Security researchers at INRIA published an attack on 64-bit block ciphers, such as 3DES and Blowfish. They show that they are able to recover plaintext when the same data is sent often enough, and show how they can use cross-site scripting vulnerabilities to send data of interest often enough. This works over HTTPS, but also works for HTTP-over-OpenVPN. See https://sweet32.info/ for a much better and more elaborate explanation.
OpenVPN's default cipher, BF-CBC, is affected by this attack.
Of the currently supported ciphers, OpenVPN currently recommends using AES-256-CBC or AES-128-CBC. OpenVPN 2.4 and newer will also support GCM. For 2.4+, we recommend using AES-256-GCM or AES-128-GCM.
AES-GCM is an AEAD cipher which means it simultaneously provides confidentiality, integrity, and authenticity assurances on the data.
The script supports the following ciphers:
And defaults to
OpenVPN 2.4 added a feature called "NCP": Negotiable Crypto Parameters. It means you can provide a cipher suite like with HTTPS. It is set to
AES-256-GCM:AES-128-GCM by default and overrides the
--cipher parameter when used with an OpenVPN 2.4 client. For the sake of simplicity, the script set both the
--ncp-cipher to the cipher chosen above.
OpenVPN 2.4 will negotiate the best cipher available by default (e.g ECDHE+AES-256-GCM)
The script proposes the following options, depending on the certificate:
It defaults to
OpenVPN uses a 2048 bits DH key by default.
OpenVPN 2.4 added support for ECDH keys. Elliptic curve cryptography is faster, lighter and more secure.
Also, generating a classic DH keys can take a long, looong time. ECDH keys are ephemeral: they are generated on-the-fly.
The script provides the following options:
It defaults to
From the OpenVPN wiki, about
Authenticate data channel packets and (if enabled) tls-auth control channel packets with HMAC using message digest algorithm alg. (The default is SHA1 ). HMAC is a commonly used message authentication algorithm (MAC) that uses a data string, a secure hash algorithm, and a key, to produce a digital signature.
If an AEAD cipher mode (e.g. GCM) is chosen, the specified --auth algorithm is ignored for the data channel, and the authentication method of the AEAD cipher is used instead. Note that alg still specifies the digest used for tls-auth.
The script provides the following choices:
It defaults to
From the OpenVPN wiki, about
Add an additional layer of HMAC authentication on top of the TLS control channel to mitigate DoS attacks and attacks on the TLS stack.
In a nutshell, --tls-auth enables a kind of "HMAC firewall" on OpenVPN's TCP/UDP port, where TLS control channel packets bearing an incorrect HMAC signature can be dropped immediately without response.
Encrypt and authenticate all control channel packets with the key from keyfile. (See --tls-auth for more background.)
Encrypting (and authenticating) control channel packets:
- provides more privacy by hiding the certificate used for the TLS connection,
- makes it harder to identify OpenVPN traffic as such,
- provides "poor-man's" post-quantum security, against attackers who will never know the pre-shared key (i.e. no forward secrecy).
So both provide an additional layer of security and mitigate DoS attacks. They aren't used by default by OpenVPN.
tls-crypt is an OpenVPN 2.4 feature that provides encryption in addition to authentication (unlike
tls-auth). It is more privacy-friendly.
The script supports both and uses
tls-crypt by default.
You can say thanks if you want!
Many thanks to the contributors and Nyr's original work.
This project is under the MIT Licence