The Point-to-Point Protocol (PPP) provides a method for transmitting datagrams over serial point-to-point links. There is a format string vulnerability in the Mac OS X Point-to-Point Protocol daemon (pppd). When pppd receives an invalid command line argument, this argument is passed to the fslprintf function. This function accepts input. Below are a few ways to identify ports in use on Mac and Windows Operating Systems: Mac. Open Terminal application and use the following command: sudo lsof -i -n -P grep TCP PC. The easiest way to view ports in use on Windows is to use Resmon.exe and view “Listening Ports”. These columns are searchable to view active ports. The rise of TCP/IP during the 1990s led to a reimplementation of most of these types of support on that protocol, and AppleTalk became unsupported as of the release of Mac OS X v10.6 in 2009. Many of AppleTalk's more advanced autoconfiguration features have since been introduced in Bonjour, while Universal Plug and Play serves similar needs.