Packetyzer!

Wireshark is the world's foremost network protocol analyzer. It lets you capture and interactively browse the traffic running on a computer network. It is the de facto (and often de jure) standard across many industries and educational institutions.

Let's face it-- there's SOOO much Wi-Fi everywhere these days, the built-in Wi-Fi tools and free utilities that used to help us understand the Wi-Fi environment just can't keep up anymore. Those tools don't help you see how many access points are in the same network, nor how many SSIDs a specific radio is broadcasting.

Netcat is a featured networking utility which reads and writes data across network connections, using the TCP/IP protocol. It is designed to be a reliable "back-end" tool that can be used directly or easily driven by other programs and scripts. At the same time, it is a feature-rich network debugging and exploration tool, since it can create almost any kind of connection you would need and has several interesting built-in capabilities.

NetStumbler is a tool for Windows that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g. It has many uses:Verify that your network is set up the way you intended, find locations with poor coverage in your WLAN, detect other networks that might be causing interference with your network, detect unauthorized "rogue" access points in your workplace, help aim directional antennas for long-haul WLAN links & use it recreationally for WarDriving.Does not work well with Win7. This software has not been updated in years and harkens back to Win Vista days. »

Microsoft Network Monitor is a packet analyzer. It enables capturing, viewing, and analyzing network data and deciphering network protocols. It can be used to troubleshoot network problems and applications on the network.

SmartSniff is a packet sniffer that capture TCP/IP packets and display them as sequence of conversations between clients and servers. You can view the TCP/IP conversations in Ascii mode (for text-based protocols, like HTTP, SMTP, POP3 and FTP) or as hex dump (for non-text base protocols, like DNS). Application can capture TCP/IP packets on your network without installing a capture driver (works only for Windows 2000/XP or greater).

NetworkMiner is a Network Forensic Analysis Tool (NFAT) for Windows. NetworkMiner can be used as a passive network sniffer/packet capturing tool in order to detect operating systems, sessions, hostnames, open ports etc. without putting any traffic on the network. NetworkMiner can also parse PCAP files for off-line analysis and to regenerate/reassemble transmitted files and certificates from PCAP files.

With Homedale you can search for Wi-Fi / WLAN Access Points and monitor their signal strength. Use the detected access points with Google Geolocation and Mozilla Location Service to locate yourself.

KisMAC is an open-source and free stumbler/scanner application for Mac OS X. It has an advantage over MacStumbler/iStumbler/NetStumbler in that it uses monitor mode and passive scanning.

How strong is your WiFi signal?

Debookee is the simplest & most powerful network traffic analyzer for macOS.

iwScanner is a wireless scanner for linux with an easy to use graphic interface.

A 802.11 wireless scanner and connection manager for Mac OS X. WiFi Scanner will detect access points and clients in ad-hoc mode if the SSID is being broadcasted. It can be used for wireless site surveys, wireless discovery, and to connect to WiFi networks. The tool reports signal strength in dBm and shows access point BSSID/MAC addresses. Features

PacketSled is next generation network forensics and breach detection.

Virtual Wifi Hotspot is a free software router for Windows based system running Windows 7, Windows 8, Windows Server 2008 R2 and Windows Server 2012.Using Virtual Wifi Hotspot, you can share any internet connection Via Wireless Internet my come from Wifi or LAN or Cable Modem or Dial-up or Cellular, etc.. The internet can be used by any Wifi device such as Laptop or desktop or Smart Phone or iPod Touch or iPhone or Ipad or Android Phone or Zune or Netbook or PS3 or wireless printer, etc.. These Wirelessls connecting devices can connect to Virtual Wifi Hotspot just like any other WiFi Router.Virtual WiFi hotspot is protected by Password and the underlaying security is WPA2 »