I think you're being too paranoid here (I don't say this often :). A ping to known good host is a benign thing. Can it be replaced with malicious thing? I'm sure it can, somebody could gain access to your router and reflash it with malware and you wouldn't even know. This is a real possibility. But it remains so regardless of presence or absence of DNS ping, so DNS ping by itself does not add any specific threat.

Calling it a "DNS ping" is just confusing or wrong. It's a DNS query.

It's dangerous because:

1. It allows them to create a database with the IP address of every internet-connected router.

2. It allows them to control routers via DNS packets, which are frequently permitted even behind firewalls.

3. It providers a cover for traffic to their servers on the DNS port.

This kind of thing is very common. It's also very dangerous and we should demand alternatives.

I called it DNS ping because it essentially serves the same function as "ping" command but on slightly different level - by checking if DNS functions.

1. This is true, but most routers check for firmware updates anyway, so there you go. Not to mention online warranty registrations, etc. which would get you into their DB anyway.

2. Unlikely, unless you have a RCE bug in your DNS implementation, in which case the router is toast without the DNS querying.

3. One query is not "traffic". It is pretty easy to distinguish between one query on boot and constant communication. Again, it is only relevant if you already have malware in your router.

#1 and #3 are not even refutations and #2 you didn't even understand. You're absolutely wrong that this isn't a security issue. The simple proof is that no secure network would ever allow a device to call home like this.

Maybe you think that because it's common it's not a problem. That's not how security works.