I am trying to configure my printer using the Hplip gui but discovery always fails On my other linux boxes manual specifying the ip address of the printer will suffice to overcome this but it does not seem to work on my Pi3B+
Cups will see & configure the printer ok but I would realy like to be able to make use of the HPlip gui as it provides information on ink levels etc.
The error given is "HPLIP cannot detect printers in your network. This may be due to existing firewall settings blocking the required ports. When you are in a trusted network environment, you may open the ports for network services like mdns and slp in the firewall. For detailed steps follow the link.
how do I configure the firewall on the PI to enable this (default raspian install)