We’ve Been Trying To Reach You About Your Firewall’s Extended Warranty Voice over IP (or VoIP) lets a user make phone calls over a computer data connection rather than a phone line. This union of computing and calling enables lots of flexibility and fancy features, but it also makes phone calling vulnerable to all the security challenges of being on the Internet. We’re talking about the protocols and infrastructure of VoIP this week, and why phone fraud that doesn’t compromise a computer system can still be an infosec issue.