mullvad-best-server

Determines the mullvad.net server with the lowest latency on macOS and Linux. On Windows, it can only check if the server is up. The reason lies with the golang network libraries, according to the go-ping library, that is used under the hood for pinging:

Please note that accessing packet TTL values is not supported due to limitations in the Go x/net/ipv4 and x/net/ipv6 packages.

Installation

Download binary from releases for your platform and unpack.

Usage

Default usage

Execute mullvad-best-server. It outputs the code, e.g. de05. You can then connect to it with e.g. wireguard using the normal shell scripts.

Command line parameters

Usage of ./mullvad-best-server:
  -c string
    	Server country code, e.g. ch for Switzerland (default "ch")
  -l string
    	Log level. Allowed values: trace, debug, info, warn, error, fatal, panic (default "info")
  -o string
    	Output format. 'json' outputs server json
  -p string
    	filter by provider, e.g. 31173 for mullvad-owned
  -t string
    	Server type, e.g. wireguard (default "wireguard")
  -timeout duration
    	Timeout for network calls as duration, e.g. 60s (default 5s)

If you want the full server information, execute mullvad-best-server -o json. It returns the full json output of the server information. The -c flag allows to give a country code. Else ch will be used.

Background

The program uses https://api.mullvad.net/www/relays/<SERVER_TYPE>/ to get the current server list, pings the ones with the right country and outputs the server with the lowest ping.

Integration into a script

I use it on my router like this (yes, I know I could have done the whole thing with jq and shell scripting, but wanted to use go for maintainability).

#!/bin/sh
set -e
LATEST_RELEASE=$(curl -sSL https://api.github.com/repos/bastiandoetsch/mullvad-best-server/releases/latest | jq -r '.assets[]| .browser_download_url' | grep Linux_arm64)
curl -sSL $LATEST_RELEASE > /root/mullvad-best-server
chmod +x /root/mullvad-best-server
/usr/bin/wg-quick down $(wg show|grep interface | cut -d: -f2)  || echo "nothing to shut down"
/usr/bin/wg-quick up "mullvad-$(/root/mullvad-best-server -c de)"

Troubleshooting

You may have to update your /usr/bin/wg-quick script for the new mullvad servers, as they have names longer than 15 chars. Replace [[ $CONFIG_FILE =~ ^[a-zA-Z0-9_=+.-]{1,15} ]]$ with [[ $CONFIG_FILE =~ ^[a-zA-Z0-9_=+.-]{1,25}$ ]] and [[ $CONFIG_FILE =~ (^|/)([a-zA-Z0-9_=+.-]{1,15})\.conf$ ]] with [[ $CONFIG_FILE =~ (^|/)([a-zA-Z0-9_=+.-]{1,25})\.conf$ ]]