Now i got it:

Anyone that runs a relay can see ip addresses of users and anyone can run a relay. Sending out notes including DM, means exposing my ip address. VPN is must.

But this is actually same with any websites, I guess.

Using #nostr is a learning experience; i lean a lot about tech.

nostr:note1j96as9amhdydwaa3xk5nlcew8pzczys3dsmg9de36lychvk2cumq3fr7a5