Connecting to the Yale VPN from Linux

2024-02-12
2 min read

In Fall 2023, Yale made some changes to its VPN login system. Instead of asking you for your username and password, the VPN client now directs you to a web-based authentication page.

This causes some trouble when logging in with openconnect. Reaching out to Yale IT doesn’t help here – they only support Cisco’s first-party AnyConnect client on Windows/Mac.

But there’s a workaround. Just tell openconnect to pretend it’s a Cisco client:

openconnect --useragent=AnyConnect access.yale.edu

And the VPN will start right up.

EDIT: Some readers have had difficulties with the setup process. I’ll add two tips here, so you won’t run into the same issues.

Firstly: Your browser will need access to the current DISPLAY or WAYLAND_DISPLAY to open a window. Unfortunately, sudo doesn’t pass environment variables to openconnect by default – so remember to use sudo -E openconnect instead.

Secondly: Running openconnect as root will start your browser as root. This may put you in a situation where:

  • Your VPN requires root permissions.
  • Your browser refuses to start with root permissions, for security reasons.

Luckily, you can configure the browser that openconnect starts via the --external-browser flag. So your final command will look something like this:

sudo -E /usr/bin/openconnect  --useragent=AnyConnect \
  --external-browser="$HOME/bin/browser-derooting-wrapper-script" \
  access.yale.edu

If you use Chromium, you can set the browser-derooting-wrapper-script to:

#!/bin/sh -e

# Chromium will run as root if the `--no-sandbox` flag is passed. 
# This is horrendously insecure. So please only use this for the VPN auth
# window. 
exec chromium --no-sandbox "$@"

But it’s better to set it to something like this:

#!/bin/sh -e

# Use `su` to start Firefox as our regular, non-root user. 
exec su --preserve-environment $YOUR_USERNAME firefox "$@"