Reference closed topic: https://www.howtogeek.com/116409/how-to-turn-your-ubuntu-laptop-into-a-wireless-access-point/
It was stated that a wifi connection cannot be shared.
Using Lubuntu 12.04 on a Dell d610 Built-in Broadcom wireless and dlink (Atheros) pcmcia card
I have successfully shared a wifi connection with a second wifi card set up as an adhoc network.
At this point it only works with no encryption
On the actual Internet connection (Lubuntu to Outside Wolrld) you must edit the connection and make sure under ip4 settings, that “Require ip addressing for this connection to complete” is checked. (this seems to activate DHCP)
Set up your adhoc network using the second wifi card with no encryption.
I have been able to connect with a win7 64bit notebook and an iphone and surf the net on both.
I was also able to share the wireless to the builtin ethernt port with a netgear wireless router. I did not check the “Require ip addressing for this connection to complete” as the router is the DHCP server.
This is useful for portable networks. We use Verizon MiFis that allow only 5 users at a time. With this setup we can get many more users on the internet or on a private network.