Geoblocking and Proxy Configurations

One consequence of spending time in Denmark is that certain web services are inaccessible due to geo-blocking. To work around this, I configured Firefox to use a proxy that forwards traffic through an SSH tunnel to a server located in Germany. The setup was somewhat cumbersome, but it worked. I repeated the process, configuring the Safari web browser to use a proxy connected through an SSH tunnel to the same server in Germany.

The next day, long after the SSH tunnel had been shut down, strange problems started to appear. I could no longer establish a VPN connection. The VPN client would briefly display an authentication window, only for it to disappear immediately. Thunderbird stopped synchronizing via IMAP (but good old mutt still worked like a charm). MacOS notified me that some software updates were available, but the App Store responded with nothing more than a cryptic error message. I also ran into issues accessing several work-related services through Firefox. None of the failing applications provided helpful error messages. I consulted some AI systems but the suggestions were hardly more useful than reboot your computer.

I suspected that something was wrong with my work-related authentication infrastructure. While that theory could not explain every symptom, it seemed like a plausible starting point. I kept digging and eventually discovered the real culprit.

Unlike Firefox, where proxy settings apply only to the browser itself, configuring a proxy in Safari actually modifies the system-wide network settings in macOS. As a result, any application relying on macOS networking services attempted to use the proxy I had configured the day before. Since the SSH tunnel was no longer running, the proxy had become nonfunctional, causing a wide range of seemingly unrelated failures. Once I removed the system-wide proxy configuration, everything immediately sprang back to life.

There are two lessons to learn here: First, changing a setting within an application should not silently create a system-wide configuration change. Safari’s proxy settings may technically behave as designed, but the fact that configuring a proxy in the browser actually modifies OS-level network settings is far from obvious and was certainly not what I expected. Second, poor error reporting remains a surprisingly common problem in modern software. Nearly every affected application failed in its own peculiar way, yet none provided enough information to identify the root cause. Instead, I was left piecing together clues from a collection of unrelated symptoms.

What surprised me most was how poorly macOS 26.5 handled the situation. A stale proxy configuration effectively broke a wide range of applications services, but the operating system offered little indication of what was wrong or where to look for the problem.