NetworkMiner

Network Miner is an open source tool that can be used as a passive network sniffer. It is available to be used on Windows, Linux, Mac, and FreeBSD operating systems. Can detect OS, sessions, hostnames, open ports and more without putting any traffic on the network itself! The data is presented in an easy to use format, that will help save valuable time to a forensic investigator. Since the release of NetworkMiner in 2007, it has become a popular tool used all over the world by incident response teams and law enforcement. 

Features:

• Live Sniffing
• Parse PCAP, PcapNG files
• Extract FTP, SMB, SMTP, POP3, and Other traffic
• Runs on Multiple Operating Systems
• Easily export information to excel files
• Audio Extraction and playback of VOIP calls
• OS Fingerprinting
• GEO IP localization
• Web Browser Tracing
• Online Ad Tracker Detection
• PRICE = FREE

In conclusion, this is software that is used all over the globe. Has great reviews and is free. It does stuff that big name software will do and doesn't cost a thing. It is cross-platform compatible meaning you don't have to buy extra equipment. On top of not needing that extra equipment, you don't also need a Linux guru to come in and do it all for you. This is just a huge cost saving to help fight crime and provide needed support. It can even allow you to grab information and export for other less technical people. Let's say your accounting team needs data it can come to them in there favorite software - excel. This can also pull out audio files to be supplied at a trial by a judge without needing more special software. This could be played from a cell phone to a jury. You can purchase the professional version to carry around on a USB drive?? How insanely crazy easy is that. Just a great overall program.

Easily perform Network Traffic Analysis in an intuitive interface.