this is my first question on this site.
My problem is that i have an old PC lying around with no WiFi adapter but it has an Ethernet adapter.
I want to connect my Raspberry pi to WiFi then connect it with an Ethernet wire to the PC to share internet but how?
My board is Raspberry pi 3 b
There are several options to achieve what you want. It depends on your use case. If you do not need to access the PC from a device on your local network then you can use NAT (Network Address Translation) which makes routing configuration simple. Here is an example How to make Raspberry Pi 4 as “WIFI” -> “Ethernet” adaptor without add any USB component?.
If you want to access the PC from a remote device then you have to use static routing. This needs additional configuration of your home hotspot/internet router. Look at this example for it: Direct Ethernet IPCam and Wifi for browsing - Networking setup.
If you want to have the PC on the same subnet of your local network you can use proxy arp. This is the most transparent setup because the PC seems to be just on the local network like any other device but it is also the most sophisticated setup. Have a look at Workaround for a wifi bridge on a Raspberry Pi with proxy arp.
