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Support Center / Setup and use / How to setup ProtonVPN on a Tomato router

How to setup ProtonVPN on a Tomato router

FreshTomato is the now only version of the Tomato community-developed custom firmware for routers still actively supported. We therefore recommend upgrading to FreshTomato and configuring it using our How to setup ProtonVPN on FreshTomato routers guide. This legacy guide is therefore primarily for reference only. 


A step-by-step guide to setup ProtonVPN on your Tomato router.

ProtonVPN can be set up on your Tomato powered router to automatically connect to a ProtonVPN server available to your subscription whenever the internet connection is established. Below is a step-by-step guide to set up your ProtonVPN router. These changes are made in the web configuration panel of your router which you can access by visiting the local IP of your router from your web browser. The two most common, the default local IP’s that most routers have are or

Opening the Router configuration panel

  • Open your browser and enter or in your browser bar. If these don’t work, you can find the default IP, username, and password in your router’s User Manual.

DNS Settings (connecting via OpenVPN protocol)

Start by configuring your DNS server requests to use ProtonVPN DNS server to prevent DNS leaks (Note, once this is set, DNS queries will not resolve unless you are successfully connected to ProtonVPN in the later stages)

  1. In the left menu, under Basic -> Network
  2. In the DNS 1 field enter the following:
  3. In the DNS 2 field enter the following:
    Screenshot of DNS settings


Openvpn Basic router settings (connecting via OpenVPN protocol)

  1. On menu located on the left side of the screen click on the VPN Tunnelling tab and then click on OpenVPN Client tab.
  2. As shown in the screenshot, set the following options:
    Start with WAN – Check the box.
    Interface Type – TUN.
    Protocol – Choose UDP.
    Server Address/Port – Enter server address in the first field and port in the second one – 1194 to you set Protocol to UDP.
    Use configuration files name as server address field(Example in the screenshot).
    Firewall – Automatic.
    Authorization Mode – TLS.
    Username/Password Authentication – Checked. Enter your OpenVPN username and password in the newly shown fields from your account page here – Note: to use our NetShield DNS filtering feature, append the suffix +f1 to your username to block malware, or +f2  to block malware, ads, and trackers (for example 123456789+f2).
    Username Authen. Only – Unchecked (default).
    Extra HMAC authorization (TLS-AUTH) – Choose Outgoing (1) from the drop-down list.
    Create NAT on tunnel – Checked.

Tomato routers that don’t have any fields for entering OpenVPN credentials:

Some Tomato routers do not have any fields for entering OpenVPN credentials. If this is your case:

  • Go to Administration -> Scripts and enter these lines into the Init field where you should change username and password to your ProtonVPN credentials:
    echo username > /tmp/password.txt
    echo password >> /tmp/password.txt
    chmod 600 /tmp/password.txt


For additional config, please enter these:

remote-cert-tls server
resolv-retry infinite
tun-mtu 1500
tun-mtu-extra 32
mssfix 1450
ping 15
ping-restart 0
reneg-sec 0
auth sha512
comp-lzo no

Keys settings and starting the VPN connection (OpenVPN Client Configuration)

  1. Proceed by clicking on Keys tab.
  2. Download the ProtonVPN configuration files and extract them.
  3. Find a configuration file for the server you were setting up and open it (in this case
    • Static key – in this field copy and paste text from <tls-auth> to </tls-auth> block.
    • Certificate Authority – in this field copy and paste text from <ca> to </ca> block.
      It should look like this: 
  4. Confirm and save all changes by clicking on Save button at the bottom of the settings page.
  5. To establish a connection, click on Start Now button. In order to check if you have connected successfully please visit the Status page.


Setting up KillSwitch on Tomato router

  • Navigate to Administration -> Scripts and under Firewall please type in:
    WAN_IF=`nvram get wan_iface`
    iptables -I FORWARD -i br0 -o $WAN_IF -j REJECT --reject-with icmp-host-prohibited
    iptables -I FORWARD -i br0 -p tcp -o $WAN_IF -j REJECT --reject-with tcp-reset
    iptables -I FORWARD -i br0 -p udp -o $WAN_IF -j REJECT --reject-with udp-reset
  • (Every client in LAN will loose internet connection in case of VPN drop.)
    WAN_IF=`nvram get wan_iface`
    iptables -I FORWARD -i br0 -s `ip address` -o $WAN_IF -j REJECT --reject-with icmp-host-prohibited
    iptables -I FORWARD -i br0 -s `ip address` -p tcp -o $WAN_IF -j REJECT --reject-with tcp-reset
    iptables -I FORWARD -i br0 -s `ip address` -p udp -o $WAN_IF -j REJECT --reject-with udp-reset
  • (Only specified IP address will loose internet access in case of VPN drop.)



Related Articles: 

How to setup ProtonVPN on DD-WRT Routers

How to setup ProtonVPN on Windows

How to setup ProtonVPN on Mac

How to setup ProtonVPN on Linux




Post Comment


  1. Justin

    Running MacOS, and I just flashed my router. How do you get the CA and Static Keys from the downloaded server config to paste in the “Keys” section? I try opening it and it just asks what program I want to use to open it.

  2. ProtonVPN Team

    Hello. You have to open those files with a text editor software. There are many online that you can use for example : Sublime Text 3

  3. bugimen

    Hi there! Should I add “keealive 10 60” to client config -> Advanced -> Custom Configuration box?

  4. ProtonVPN Team

    Hello Bugimen. This setting is pushed from the server side so it does not matter what you type in the config.

  5. linksys tech support

    ProtonVPN gives more security to a router. Your tips are very informative and anyone can set VPN in a very simple way. Nice article for the user.

  6. Fred

    You say

    In the left menu, under Basic -> Network
    In the DNS 1 field enter the following:
    In the DNS 2 field enter the following:

    The IP connects to Google DNS servers which I don’t want to use. If I remove that entry, and leave only the IP, I get no DNS service. If I add a different public DNS service e.g. openDNS I get DNS services back again. This indicates that protonvpn’s DNS server at is not working for me. What do I need to do to get protonvpn to provide me with DNS services. Thanks.
    (Linksys WRT54G with tomato firmware ver.1.28)

  7. ProtonVPN Team

    Hello Fred, each of our servers has an integrated DNS server inside them. OpenDNS and Google Domain name servers are dedicated, we do not provide a separate Domain Name Server yet. When you connect to a VPN server, DNS should be fetched automatically from it. If you are experiencing DNS leaks, please write us an e-mail via and we will do some extensive troubleshooting.

  8. User

    Please fix the wrong How to:

    Still no VPN Connection by useing as only one DNS server.
    No problems to get VPN connection ba useing good known DNS server like or other.

    Proton VPN service mean by email:
    – proton VPN dont provide DNS server on this time
    – are no DNS serever

  9. ProtonVPN Team

    Hello, If you are using free servers, then you have to use in the DNS settings, if not, will work and will provide the DNS servers of the VPN server.

  10. Tatibyte

    Thanks guys, works fine the connection! thanks for all!

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