VOIP numbers have two identifiers: caller ID and the CNAM. Caller ID is the number you see on your phone when a call comes in and it is very easy to fake, at least for now. CNAM however, is very difficult to tamper with, so many spoofers don’t even bother with trying to alter it. Also, there are CNAM registries and databases available for professional queries. This makes tracing a CNAM a feasible option if you have the time, tech skills, and energy for it.