Ethereal
Ethereal® is used by network professionals around the world for troubleshooting, analysis…
21 Alternatives To Ethereal

Cocoa Packet Analyzer
Native Cocoa app for capturing and analyzing packets.
Homedale
With Homedale you can search for Wi-Fi / WLAN Access Points and monitor their signal strength.
Intercepter-NG
Intercepter-NG is a multifunctional network toolkit for various types of IT specialists.
Kismet
Kismet is an 802.11 layer2 wireless network detector, sniffer, and intrusion detection system.

LANGuardian
NetFort LANGuardian is a network visibility solution which uses deep packet inspection to monitor, troubleshoot, and report on user & network activity.

ManageEngine Network Configuration Manager
Network Configuration Manager is a multi-vendor network change, configuration and compliance management solution for switches and routers.
NetStumbler
Official source of information about Netstumbler.
NetworkMiner
NetworkMiner is a Network Forensic Analysis Tool (NFAT) for Windows.
Nmap
Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.
PsPing
PsPing is a command-line utility for measuring network performance.
Ubiquiti Network Management System
Ubiquiti Network Management System manages all the EdgeMAX, EdgeSwitch, airMAX and UFiber devices.
WiFi Explorer
WiFi Explorer is a tool to scan, find, and troubleshoot wireless networks.

Wifi Analyzer
Wifi Analyzer is a handy tool which helps you to select a better channel for your wireless router.

Wireshark
Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
netcat
Netcat is a featured networking utility which reads and writes data across network connections…