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323 lines
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Markdown
323 lines
13 KiB
Markdown
---
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layout: doc
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title: VPN
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permalink: /doc/vpn/
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redirect_from:
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- /doc/privacy/vpn/
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- /en/doc/vpn/
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- /doc/VPN/
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- /wiki/VPN/
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---
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How To make a VPN Gateway in Qubes
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==================================
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Although setting up a VPN connection is not by itself Qubes specific, Qubes includes a number of tools that can make the client-side setup of your VPN more versatile and secure. This document is a Qubes-specific outline for choosing the type of VM to use, and shows how to prepare a ProxyVM for either NetworkManager or a set of fail-safe VPN scripts.
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Please refer to your guest OS and VPN service documentation when considering the specific steps and parameters for your connection(s); The relevant documentation for the Qubes default guest OS (Fedora) is [Establishing a VPN Connection.](https://docs.fedoraproject.org/en-US/Fedora/23/html/Networking_Guide/sec-Establishing_a_VPN_Connection.html)
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### NetVM
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The simplest case is to set up a VPN connection using the NetworkManager service inside your NetVM. Because the NetworkManager service is already started, you are ready to set up your VPN connection. However this has some disadvantages:
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- You have to place (and probably save) your VPN credentials inside the NetVM, which is directly connected to the outside world
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- All your AppVMs which are connected to the NetVM will be connected to the VPN (by default)
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### AppVM
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While the NetworkManager service is not started here (for a good reason), you can configure any kind of VPN client in your AppVM as well. However this is only suggested if your VPN client has special requirements.
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### ProxyVM
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One of the best unique features of Qubes OS is its special type of VM called a ProxyVM. The special thing is that your AppVMs see this as a NetVM (or uplink), and your NetVMs see it as a downstream AppVM. Because of this, you can place a ProxyVM between your AppVMs and your NetVM. This is how the default sys-firewall VM functions.
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Using a ProxyVM to set up a VPN client gives you the ability to:
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- Separate your VPN credentials from your NetVM.
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- Separate your VPN credentials from your AppVM data.
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- Easily control which of your AppVMs are connected to your VPN by simply setting it as a NetVM of the desired AppVM.
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Set up a ProxyVM as a VPN gateway using NetworkManager
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------------------------------------------------------
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1. Create a new VM, name it, click the ProxyVM radio button, and choose a color and template.
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2. Add the `network-manager` service to this new VM.
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3. Set up your VPN as described in the NetworkManager documentation linked above.
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4. (Optional) Make your VPN start automatically.
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Edit `/rw/config/rc.local` and add these lines:
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```bash
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# Automatically connect to the VPN once Internet is up
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while ! ping -c 1 -W 1 1.1.1.1; do
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sleep 1
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done
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PWDFILE="/rw/config/NM-system-connections/secrets/passwd-file.txt"
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nmcli connection up file-vpn-conn passwd-file $PWDFILE
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```
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You can find the actual "file-vpn-conn" in `/rw/config/NM-system-connections/`.
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Create directory `/rw/config/NM-system-connections/secrets/` (You can put your `*.crt` and `*.pem` files here too).
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Create a new file `/rw/config/NM-system-connections/secrets/passwd-file.txt`:
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```
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vpn.secrets.password:XXXXXXXXXXXXXX
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```
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And substitute "XXXXXXXXXXXXXX" for the actual password.
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The contents of `passwd-file.txt` may differ depending on your VPN settings. See the [documentation for `nmcli up`](https://www.mankier.com/1/nmcli#up).
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5. (Optional) Make the network fail-close for the AppVMs if the connection to the VPN breaks.
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Edit `/rw/config/qubes-firewall-user-script` and add these lines:
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```bash
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# Block forwarding of connections through upstream network device
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# (in case the vpn tunnel breaks)
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iptables -I FORWARD -o eth0 -j DROP
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iptables -I FORWARD -i eth0 -j DROP
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```
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6. Configure your AppVMs to use the new VM as a NetVM.
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7. Optionally, you can install some [custom icons](https://github.com/Zrubi/qubes-artwork-proxy-vpn) for your VPN
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Set up a ProxyVM as a VPN gateway using iptables and CLI scripts
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----------------------------------------------------------------
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This method is more involved than the one above, but has anti-leak features that also make the connection _fail closed_ should it be interrupted.
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It has been tested with Fedora 23 and Debian 8 templates.
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1. Create a new VM, name it, click the ProxyVM radio button, and choose a color and template.
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Note: Do not enable NetworkManager in the ProxyVM, as it can interfere with the scripts' DNS features.
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If you enabled NetworkManager or used other methods in a previous attempt, do not re-use the old ProxyVM...
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Create a new one according to this step.
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If your choice of TemplateVM doesn't already have the VPN client software, you'll need to install the software in the template before proceeding.
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Disable any auto-starting service that comes with the software package.
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For example for OpenVPN.
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sudo systemctl disable openvpn.service
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You may also wish to install `nano` or another simple text editor for entering the scripts below.
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2. Set up and test the VPN client.
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Make sure the VPN VM and its TemplateVM is not running.
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Run a terminal (CLI) in the VPN VM -- this will start the VM.
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Then create a new `/rw/config/vpn` folder with.
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sudo mkdir /rw/config/vpn
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Copy your VPN config files to `/rw/config/vpn`.
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Your VPN config file should be named `openvpn-client.ovpn`) so you can use the scripts below as is without modification.
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Otherwise you would have to replace the file name.
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`openvpn-client.ovpn` contents:
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* Files accompanying the main config such as `*.crt` and `*.pem` should also go to `/rw/config/vpn` folder.
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* Files referenced in `openvpn-client.ovpn` should not use absolute paths such as `/etc/...`.
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The VPN scripts here are intended to work with commonly used `tun` interfaces, whereas `tap` mode is untested.
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Also, the config should route all traffic through your VPN's interface after a connection is created; For OpenVPN the directive for this is `redirect-gateway def1`.
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sudo nano /rw/config/vpn/openvpn-client.ovpn
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Make sure it already includes or add:
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redirect-gateway def1
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The VPN client may not be able to prompt you for credentials when connecting to the server.
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Create a file in the `/rw/config/vpn` folder with your credentials and using a directive.
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For example for OpenVPN, add:
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auth-user-pass pass.txt
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Save file `/rw/config/vpn/openvpn-client.ovpn`.
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Make sure a `/rw/config/vpn/pass.txt` file actually exists.
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sudo nano /rw/config/vpn/pass.txt
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Add:
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username
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password
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Replace `username` and `password` with your actual username and password.
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**Test your client configuration:**
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Run the client from a CLI prompt in the 'vpn' folder, preferably as root.
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For example:
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sudo openvpn --cd /rw/config/vpn --config openvpn-client.ovpn
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Watch for status messages that indicate whether the connection is successful and test from another VPN VM terminal window with `ping`.
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ping 8.8.8.8
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`ping` can be aborted by pressing the two keys `ctrl` + `c` at the same time.
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DNS may be tested at this point by replacing addresses in `/etc/resolv.conf` with ones appropriate for your VPN (although this file will not be used when setup is complete).
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Diagnose any connection problems using resources such as client documentation and help from your VPN service provider.
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Proceed to the next step when you're sure the basic VPN connection is working.
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3. Create the DNS-handling script.
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sudo nano /rw/config/vpn/qubes-vpn-handler.sh
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Edit and add:
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~~~
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#!/bin/bash
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set -e
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export PATH="$PATH:/usr/sbin:/sbin"
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case "$1" in
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up)
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# To override DHCP DNS, assign DNS addresses to 'vpn_dns' env variable before calling this script;
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# Format is 'X.X.X.X Y.Y.Y.Y [...]'
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if [[ -z "$vpn_dns" ]] ; then
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# Parses DHCP foreign_option_* vars to automatically set DNS address translation:
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for optionname in ${!foreign_option_*} ; do
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option="${!optionname}"
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unset fops; fops=($option)
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if [ ${fops[1]} == "DNS" ] ; then vpn_dns="$vpn_dns ${fops[2]}" ; fi
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done
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fi
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iptables -t nat -F PR-QBS
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if [[ -n "$vpn_dns" ]] ; then
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# Set DNS address translation in firewall:
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for addr in $vpn_dns; do
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iptables -t nat -A PR-QBS -i vif+ -p udp --dport 53 -j DNAT --to $addr
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iptables -t nat -A PR-QBS -i vif+ -p tcp --dport 53 -j DNAT --to $addr
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done
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su - -c 'notify-send "$(hostname): LINK IS UP." --icon=network-idle' user
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else
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su - -c 'notify-send "$(hostname): LINK UP, NO DNS!" --icon=dialog-error' user
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fi
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;;
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down)
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su - -c 'notify-send "$(hostname): LINK IS DOWN !" --icon=dialog-error' user
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;;
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esac
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~~~
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Save the script.
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Make it executable.
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sudo chmod +x /rw/config/vpn/qubes-vpn-handler.sh
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4. Configure client to use the DNS handling script. Using openvpn as an example, edit the config.
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sudo nano /rw/config/vpn/openvpn-client.ovpn
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Add the following.
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script-security 2
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up 'qubes-vpn-handler.sh up'
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down 'qubes-vpn-handler.sh down'
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Remove other instances of lines starting with `script-security`, `up` or `down` should there be any others.
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Save the script.
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**Restart the client and test the connection again** ...this time from an AppVM!
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5. Set up iptables anti-leak rules.
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Edit the firewall script.
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sudo nano /rw/config/qubes-firewall-user-script
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Clear out the existing lines and add:
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~~~
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#!/bin/bash
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# Block forwarding of connections through upstream network device
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# (in case the vpn tunnel breaks):
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iptables -I FORWARD -o eth0 -j DROP
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iptables -I FORWARD -i eth0 -j DROP
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ip6tables -I FORWARD -o eth0 -j DROP
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ip6tables -I FORWARD -i eth0 -j DROP
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# Block all outgoing traffic
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iptables -P OUTPUT DROP
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iptables -F OUTPUT
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iptables -I OUTPUT -o lo -j ACCEPT
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# Add the `qvpn` group to system, if it doesn't already exist
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if ! grep -q "^qvpn:" /etc/group ; then
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groupadd -rf qvpn
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sync
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fi
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sleep 2s
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# Allow traffic from the `qvpn` group to the uplink interface (eth0);
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# Our VPN client will run with group `qvpn`.
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iptables -I OUTPUT -p all -o eth0 -m owner --gid-owner qvpn -j ACCEPT
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~~~
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Save the script.
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Make it executable.
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sudo chmod +x /rw/config/qubes-firewall-user-script
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5. Set up the VPN's autostart.
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sudo nano /rw/config/rc.local
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Clear out the existing lines and add:
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~~~
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#!/bin/bash
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VPN_CLIENT='openvpn'
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VPN_OPTIONS='--cd /rw/config/vpn/ --config openvpn-client.ovpn --daemon'
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su - -c 'notify-send "$(hostname): Starting $VPN_CLIENT..." --icon=network-idle' user
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groupadd -rf qvpn ; sleep 2s
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sg qvpn -c "$VPN_CLIENT $VPN_OPTIONS"
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~~~
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If you are using anything other than OpenVPN, change the `VPN_CLIENT` and `VPN_OPTIONS` variables to match your VPN software.
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Save the script.
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Make it executable.
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sudo chmod +x /rw/config/rc.local
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6. Restart the new VM!
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The link should then be established automatically with a popup notification to that effect.
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Usage
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-----
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Configure your AppVMs to use the VPN VM as a NetVM...
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If you want to be able to use the [Qubes firewall](/doc/firewall), create a new FirewallVM (as a ProxyVM) and set it to use the VPN VM as its NetVM.
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Then, configure AppVMs to use your new FirewallVM as their NetVM.
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If you want to update your TemplateVMs through the VPN, enable the `qubes-updates-proxy` service in your new FirewallVM.
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You can do this in the Services tab in Qubes VM Manager or on the command-line:
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qvm-service -e <name> qubes-updates-proxy
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Then, configure your templates to use your new FirewallVM as their NetVM.
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Troubleshooting
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---------------
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* Always test your basic VPN connection before adding scripts.
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* Test DNS: Ping a familiar domain name from an appVM. It should print the IP address for the domain.
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* For scripting: Ping external IP addresses from inside the VPN VM using `sudo sg qvpn -c 'ping ...'`, then from an appVM using just `ping ...`. Once the firewall rules are in place, you will have to use `sudo sg` to run any IP network commands in the VPN VM.
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* Use `iptables -L -v` and `iptables -L -v -t nat` to check firewall rules. The latter shows the critical PR-QBS chain that enables DNS forwarding.
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