If you are a business that has a site or an app and you are receiving internet traffic to the site or app the you will be able to see the ip-addresses coming to your site or app.

Normally an online business has a site or app as the destination and someone surfing the web is the source. In internet terms this means you need a source address, a destination address and traffic (an email or a browser action) between the two. By the same token, if a letter does not have a destination address, you will not get a letter, and there is nothing to track it back to. If you don’t have the letter, then you also won’t have a return address. If you receive the letter, then you can figure out where the letter came from by looking at the return address.