Traditional Method

• If calls are annoyances, such as telemarketers, you should contact your telephone provider and file a nuisance complaint, suggests the Privacy Rights Clearinghouse. For dangerous calls, such as death threats, you should file a report with the police.
  
  

Considerations

• Famed hacker Kevin Mitnick devised a scheme to find out a blocked number by routing the calls over a voice over IP (VoIP) service to a server with software that analyzes the header in the data transmission. This is an inexpensive option but not an easy one for a novice computer user.
  
  

Tip

• In 2009, "Wired" magazine reported that a service called TrapCall could reveal the number and possibly the address of an unwanted caller. The basic service if free and lets you block callers; getting the caller's name comes at a premium.