The NESSUS - Nessus Network Security Scanner File is a file created by Nessus- an application that scans for network vulnerability
XML formatting. is used with NESSUS files and although,on Nessus version 4, Version 2 of the XML format was introduced, it's still backward compatible with version 1 files.
A NESSUS - Nessus Network Security Scanner File can saving the results of each network security scan along with the policies employed for set scan. These scanning results - of either your home or corporate network - can then be imported or just saved for review.