Configure a Guest WiFi network with dd-wrt firmware
Refer to the the tutorials:
Guest Network on the DD-WRT Wiki‘ and
Guest WiFi + abuse control for beginners

My objective of a guest network is to offer isolated, yet protected, access to the Internet. Guest users should not have access to my private LAN. This can be achieved with the following settings:
Wireless Basic Settings (‘Virtual Interfaces’): AP isolation enabled.
Network Configuration: Unbridged, NAT enabled.
You will need to assign a dedicated network range and enable DHCP.

Configure a Guest WiFi network
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