Charles got a new Eero mesh router all set up (Eero is a sponsor of the TWiT Network), but now he gets a warning that his router can be seen online. Leo says that the best thing a router can do is be invisible by not responding to any online queries. It's called Stealth Mode. That's what GRC's Shields Up will test. Most routers have PING turn on by default. But you can turn it off in the security settings. Also, turn off universal plug n play and file sharing.