Device access (firewall) options in Connectify Hotspot
Connectify Hotspot has a simple firewall for your hotspot network. In Connectify Hotspot 27 it is called Device access, and it decides two things: whether devices on your hotspot can use the internet, and whether they can reach your PC and each other. You can set this for all devices at once, or for one device at a time.
For all devices: Settings > Security and privacy > Device access
Click Settings, then Security and privacy. The Device access section has two switches:
- Devices can use the internet: "Turn off to let devices reach only this PC and each other. You can still allow single devices on the Clients screen."
- Devices can reach this PC and each other: "Needed for file sharing, printing and casting between devices. Leave off on public networks."

Both are on by default, and changes apply right away, even while the hotspot is running. Turning one off applies to every device, including those already on your hotspot. You can then turn it back on for single devices on the Clients screen (see below).
These two switches need Hotspot PRO or MAX. On Hotspot Lite they show a PRO badge, and clicking one shows you how to upgrade.
Devices can use the internet is also on the Protection card of the Hotspot screen, next to Block ads. It is the same setting. Its All security settings link takes you to Security and privacy.

For one device: the Clients screen
Click Clients and select the device. Its Device details panel has two switches:
- Can use the internet
- Can reach this PC and others
These work on every edition, including Hotspot Lite. A device that can't use the internet shows a No internet tag in the Clients list.

While the hotspot is running, the switch on each device in the On your hotspot now list on the Hotspot screen does the same as Can use the internet.
There is no Block button. To keep a device off the internet, turn off Can use the internet for it. (The Remove button only takes a device that has left off the list. It does not block it.)
Troubleshooting
If a device on your hotspot can't get online, or can't reach your PC or another device, first check Settings > Security and privacy > Device access, and then the device's own switches on the Clients screen, to make sure its access isn't turned off.
To reach a server or a shared folder on the PC running the hotspot, see Can I access a server running on the Hotspot computer?