Bulkhead by S4NT0S

Give every Firefox container its own Mullvad server. Your Work, Banking and Personal tabs browse from different IP addresses at the same time. If a container's server stops working, Bulkhead blocks that container and tells you why.

Bulkhead is a companion for the Mullvad VPN app. Every Mullvad server runs a SOCKS5 proxy inside the tunnel, and Bulkhead sends each container through a different one while the app stays connected as usual.

Why you'd want it

• A separate IP address per container. Sites in different containers can't tie you together by address.
• A kill switch per container. If a container's server is down, unchecked or exiting in the wrong place, its tabs are blocked until it checks out.
• Guards against other proxy extensions. If another extension takes over a container's route or sends it direct, Bulkhead blocks it instead of letting it slip out.
• Real exit checks. Each server is tested against am.i.mullvad.net to see where traffic really exits.
• The full server list built in. Search it, keep favourites, and see which servers your other containers already use.
• Works outside containers too. Normal tabs and private windows can get a server, or follow whichever server the Mullvad app is connected to.
• A block page that tells you why. It names the container, the reason and the address you tried to open.
• Warned when a server is retired. If Mullvad takes away a server you use, you get a one-click move to one nearby.

Better than a plain proxy setting

Multi-Account Containers, Sidebery and FoxyProxy can all give a container a proxy, but they don't check where your traffic comes out, and they won't block a container while its server is down or unverified. Bulkhead does, and it has Mullvad's server list built in.

Works with Multi-Account Containers

Use Multi-Account Containers to choose which sites open in which container, and Bulkhead to choose where each container exits. Just don't set a proxy for the same container in both: Bulkhead will block that container and tell you another proxy took over.

What you need

• A Mullvad account, with the Mullvad app connected
• Firefox 142 or later, on desktop
• Two Firefox settings changed by hand (the settings page shows which, and why)

Coming next: IVPN support. Until then, your own SOCKS5 server, such as an SSH tunnel or a VPS, works as a custom exit with the same checks.

Open source. GPL-3.0 with no build step, code on GitHub. It has no accounts or analytics and collects no data.

Unofficial. Not affiliated with, endorsed by, or supported by Mullvad VPN AB.