DES181419, there's no easy way to save IP's. People have asked for buddy lists, but the numbers change too much for many sources.

You can turn on the search column that shows the Location(s)--the IP numbers--of the source(s). Right-click column headers to select the optional ones.

If it's a single number, you can try to copy and paste it later in the Direct Connect search box sadlander mentioned.

However, many IP's are dynamic and change, so the easiest way to find the file/host is just do do another search. I found saved IP lists get stale pretty quickly and are too much hassle to maintain.