Windows Firewall issue when connecting from expo

Question

I am having windows firewall issues connecting to the react-native packager from expo on both the VS android emulator and an Android hardware device.

The error I am getting in Expo is "Uncaught Error: Packager is not running at http:/192.168.1.8:19001".

This is not the usual connect issue you have with Expo as documented in Could not load exp:// Something went wrong . I've already lain on that bed of pain. I now have my environment variable set up like so...

set REACT_NATIVE_PACKAGER_HOSTNAME=192.168.1.8

This is something entirely new. Everything was working fine up to the last windows update. The reason I know it is a windows firewall issue is that when I turn off the firewall everything starts working.

But this is not a fix. I would really like to turn my firewall back on. I've looked at the firewall rules and I see Expo XDE and Node.js in the inbound rules.

What is the real fix for this? I have a feeling a lot of people are suddenly having this issue.

Answer 1

Ok. So the problem turned out to be multiple installations node.js. My firewall had rules for one installation of node.js while react-native was using another installation.

So the firewall had inbound rules for a node.js installation that was installed by Visual Studio. This installation was older then the newer installation of node.js which I installed as a part of getting react-native working.

So to fix the problem I had to change the inbound firewall rules for node.exe to specify a path to the newer rather than the older installation of node.exe.

The remaining mystery is why this suddenly became a problem when react-native had been working fine. I suspected the most recent windows update but I don't see any changes to Windows Firewall in that update.

So what I learned: (1) even though Windows Firewall has notifications on, it doesn't notify you when blocking an inbound connection for a process named in an existing rule; (2) I really need to pay attention to multiple installations of the same tool set. Multiple installs of node.js was the root issue in this problem and I recently had issues with multiple installs of the Android tool adb.exe

Answer 2

Device not able to connect to development server is a result of windows firewall advance security blocking node.js javascript runtime and or multiple installations of node.js javascript runtime in the inbound rules.

Go to windows firewall advance security, Go to inbound Rules Check for multiple installations of node.js javascript runtime in the list, delete all multiple installations of node.js javascript runtime Check if node.js runtime is checked, if not right click and go to properties Under Actions check to allow the connection

This solves the problem for me.