Slack Desktop app behind a SOCK proxy on macOS

Originally posted at http://www.vojtechvitek.com/posts/slack-desktop-app-behind-a-sock-proxy-on-macos-14045333

Are you behind a company network (or VPN) that restricts access to Slack? Or does the company force you to install a custom root certificate in order for you to log into a certain Slack team using SSO? Here's a solution for you.. First of all, you need a server that is outside of the restricted company network. Create a SOCK proxy to that server using SSH and keep the connection open:

ssh -D 8000 [username]@[server]

Go to System Preferences
Select your network interface (most probably WIFI or Wired connection)
Click on Advanced..
Click on Proxies tab
Select and check off Automatic Proxy Configuration
Paste in this URL: https://raw.githubusercontent.com/VojtechVitek/sock-proxy/master/slack-proxy.pac (you can see the content of the file below)
Hit OK and Apply the changes

Applying proxy.pac configuration file hosted on Github on macOS Note: The proxy.pac file must be served from http[s]. Local files don't work on recent macOS systems, since file:// URLs are sandboxed. Use Github :)

function FindProxyForURL(url, host) {
    
    if (shExpMatch(host, "*.slack-msgs.com")) {        
        // Use SOCK proxy,
        // or fall back to a DIRECT traffic.
        // ssh -D 8000 [user]@[server]
        return "SOCKS 127.0.0.1:8000; DIRECT";
    }
    
    return "DIRECT";
}

Here you go. Slack is working again. Enjoy!

VojtechVitek/sock-proxy

Slack Desktop app behind a SOCK proxy on macOS