How to share laptop //localhost with cell phone users using router

Question

I want users to connect to Netgear router and access an app hosted on my laptop at localhost:9002. This will be in a place without cell phone or internet access.

The Windows 10 laptop is connected to the "Internet" port of the Netgear router. I have tried 192.168.137.1; 10.0.2.2 (from an answer to a similar question); 169.254.232.76 (autoconfigured IPV4 address for Ethernet adapter). I have tried this both with entering the base IP addresses above and with :9002 for the port. This is being entered in my phone's browser.

I have also tried this with the laptop connected to an ethernet port on the router rather than the internet port.

Here are my network connections (again, Wi-Fi will not be available): Network connections Ethernet and Ethernet through Netgear router

Do I need a DNS or something? Or is it a setting I'm missing? Any help is appreciated.

Answer 1

I assume you have a router with one WAN port, several LAN ports and WiFi capability. And there is no need to connect to this app from Internet.

You just connect your laptop to any LAN ports, configure DHCP server inside your Netgear router (otherwise you'll have to correctly assign ip addresses from the same subnet for your laptop and your phone). This way your router will be working as a switch bridging your devices in the same network segment, and you'll have connectivity from your phone to your laptop.

Also be sure that your app binds to the laptop's ip address like 192.168... (whichever is configured) and not to 127.0.0.1 (which is the "synonym" of the localhost)

UPD

Check the Windows Firewall, maybe you disabled net access for python when you first run your script binding to 192.168.1.2.

Answer 2

Wi-Fi will not be available.

Supplementing the existing answer to this question:

• Wi-Fi needs to be available on the router, at least to for the phones to connect to. The router is what actually connects your phone and laptop, allowing e.g. your phone browser access to the laptop and whatever app it's running.

• You should make sure there are no firewalls between the phone(s) and the application. This could be a firewall on the router or on the laptop itself (e.g. Windows firewall).

• Be aware that you may need to port forward 9002 to the local IP address of the laptop in the router. That is, requests for port 9002 that come from another device on the network (e.g. a phone) need to be routed to the correct computer (e.g. the laptop); otherwise, the router may simply ignore those requests.

Do I need a DNS or something?

Likely not, unless you want to use a name rather than an IP address to access the laptop (e.g. as laptop.local:9002 versus e.g. 192.168.1.X:9002).

Note that while you can theoretically redirect localhost to another computer (rather than the local device) with DNS, in practice software such as browsers don't necessarily check that name for its associated IP (since it is typically mapped to 127.0.0.1).