It's like putting your phone number on the wall of a bathroom stall. Maybe you won't get a lot of prank calls, maybe you will. It's a crapshoot.
The thing is, posting your public IP is like asking for a number of hackers to start probing your network for lapses in security. Not because you're a juicy target, but simply because you put the information out there. That's been bog standard for the internet for 20 years now.
Sure, IP addresses can be found through various ways, but having them out for everybody to see is just asking for more trouble than it is worth. You're making yourself a target and creating more work for yourself if you're constantly getting hacked because of it.
Like I don't even want to do anything malicious and I immediately started up a traceroute.
If the router supports hairpinning, the IP request can be resolved locally.
The domain name lookup would be a different issue and could potentially need to be resolved externally, but the router's DNS cache should be able to answer eventually.
Depends. If the zone responsible for whatever resolves to that IP is hosted locally - then DNS request would stay local.
If the service behind that IP is running locally - then all traffic would stay local. Network stack would be smart enough to not run circles to find itself.
Yeah, the router ought to know that public IP belongs to a device in its own network unless you're doing stuff like running your own router behind an ISP provided router and just forwarding ports instead of maintaining IP assignment / routing tables
It's not internal, but there are other private address ranges beyond 192.168.0.0/16. 10.0.0.0/8 is another common one. Container platforms like to use 172.16.0.0/12.
Oh wow.... Didn't know this lol. I thought that OP would be using their private IP to access their homserver from home. Turns out I got completely confused....