Can't connect to Flask web service, connection refused
Question:
I’m trying to run a simple web server on a Raspberry Pi with Flask. When I run my Flask app, it says:
running on http://127.0.0.1:5000/
But when I enter this address on my laptop’s in Chrome, I get
ERR_CONNECTION_REFUSED
I can open 127.0.0.1:5000 on the Raspberry Pi’s browser. What do I need to do to connect from another computer?
Answers:
You will have to run the development server such that it listens to requests on all interfaces and not just the local one
Ask Flask to listen on 0.0.0.0:PORT_NUMBER
or any other port you may choose
Run your app like this:
if __name__ == '__main__':
app.run(host='0.0.0.0')
It will make the server externally visible. If the IP address of the machine is 192.168.X.X then, from the same network you can access it in 5000 port. Like, http://192.168.X.X:5000
when you are running the server via flask run change it to flask run --host=0.0.0.0
to connect, find the IPV4 address of the server that your script is running on. On the same network, go to http://[IPV4 address]:5000
A reason could also be in firewall refusing incoming connections on port 5000. Try:
sudo ufw allow 5000
app.run(host='0.0.0.0',port=5000)
if you run your app in this way then your server will be visible externally.
Steps by Setp:
-
Run your app by using the following command
app.run(host=’0.0.0.0′,port=5000)
-
Go to the window cmd . Type ipconfig and get the get the IPV4 adress suppose your IPV4 address is 192.168.X.X
-
Go to the mobile browser and type the 192.168.X.X:5000
If you have debug = True inside your app.run(), then it will not be visible to other machines either. Specify host and port inside app.run() without the debug = True.
- Both devices must be connected to same network.
- Use
app.run(host='0.0.0.0',port=5000) and run with your own Ipv4
address like his http://[Your Ipv4 address]:5000
- If you are connecting this with android app then don’t forget to
put INTERNET permission in manifest file.
Well i was also here to know answer but i guess i found out problem. The reason is that you may not activated or run flask that’s why it is showing error. For that you have to start from terminal "flask run" and then surely your flask will run…
The issue may occur, if VPN is on, so try to switch it off.
Contrary to popular believe 127.0.0.1 is not the same a localhost.
I solved the issue above by setting 127.0.0.1 explicitly on both ends.
On MacOS 12.4 (Monterey) I couldn’t load localhost nor my local IP but it worked with both of these:
- 0.0.0.0
- 127.0.0.1
Just change the URL in the browser if it loads with "localhost".
I’m trying to run a simple web server on a Raspberry Pi with Flask. When I run my Flask app, it says:
running on http://127.0.0.1:5000/
But when I enter this address on my laptop’s in Chrome, I get
ERR_CONNECTION_REFUSED
I can open 127.0.0.1:5000 on the Raspberry Pi’s browser. What do I need to do to connect from another computer?
You will have to run the development server such that it listens to requests on all interfaces and not just the local one
Ask Flask to listen on 0.0.0.0:PORT_NUMBER
or any other port you may choose
Run your app like this:
if __name__ == '__main__':
app.run(host='0.0.0.0')
It will make the server externally visible. If the IP address of the machine is 192.168.X.X then, from the same network you can access it in 5000 port. Like, http://192.168.X.X:5000
when you are running the server via flask run change it to flask run --host=0.0.0.0
to connect, find the IPV4 address of the server that your script is running on. On the same network, go to http://[IPV4 address]:5000
A reason could also be in firewall refusing incoming connections on port 5000. Try:
sudo ufw allow 5000
app.run(host='0.0.0.0',port=5000)
if you run your app in this way then your server will be visible externally.
Steps by Setp:
-
Run your app by using the following command
app.run(host=’0.0.0.0′,port=5000)
-
Go to the window cmd . Type ipconfig and get the get the IPV4 adress suppose your IPV4 address is 192.168.X.X
-
Go to the mobile browser and type the 192.168.X.X:5000
If you have debug = True inside your app.run(), then it will not be visible to other machines either. Specify host and port inside app.run() without the debug = True.
- Both devices must be connected to same network.
- Use
app.run(host='0.0.0.0',port=5000)and run with your own Ipv4
address like his http://[Your Ipv4 address]:5000 - If you are connecting this with android app then don’t forget to
put INTERNET permission in manifest file.
Well i was also here to know answer but i guess i found out problem. The reason is that you may not activated or run flask that’s why it is showing error. For that you have to start from terminal "flask run" and then surely your flask will run…
The issue may occur, if VPN is on, so try to switch it off.
Contrary to popular believe 127.0.0.1 is not the same a localhost.
I solved the issue above by setting 127.0.0.1 explicitly on both ends.
On MacOS 12.4 (Monterey) I couldn’t load localhost nor my local IP but it worked with both of these:
- 0.0.0.0
- 127.0.0.1
Just change the URL in the browser if it loads with "localhost".