Just like any webserver, the relays can see the IP. Clients too, if the client is a webserver. And then the 3rd thing that you may be more concerned with is when a client auto-loads a link or image from a note, as those can be more of a targeted attack to collect your IP via you looking at a note or DM.
Discussion
correct - this is what the WhiteHAT guy did few months ago doxed geoip of many in realtime - just to demo. Also any CROSS-LINK to CDN server can see who is loading image/video - this has nothign to do with nostr. only TEXT notes are covered in this topic