Check out these tools recommended by Gearhead author Mark Gibbs.
For more than 25 years, Gibbs has done just about everything in the networking business short of hacking into NORAD. He worked as an executive in various companies, has created companies, and has consulted on product and service development for many businesses.
As an author, he has written four books and numerous articles about networking and computer technology. Gibbs has been a regular contributor to Network World since 1995 and pens (well, keyboards) the weekly Gearhead column.