sudo iptables -t nat -I PREROUTING -p tcp -d 192.168.1.60/32 --dport 7777 -j DNAT --to-destination 127.0.0.1:7777
Important: to check the result, go to another pc and query:
I checked on the same pc as Electrum runs, and apparently that doesn't work.
Next step is to secure the line .