Angry IP Scanner is an easy-to-use open-source network and Internet scanner. (Ignore the name, there's nothing angry about it in any way.)
The interface is straightforward. Visible options and controls are kept to a minimum, the target host name and IP range are set to sensible defaults, and if you're scanning the local network you'll probably be able to launch the program and immediately click "Start".
The program uses multi-threaded scanning to keep performance high, and displays basic details about each device as it's discovered: IP address, ping time, host name and open ports. Optional fields include TTL, Filtered Ports, Web detect, HTTP Sender, NetBIOS Info, MAC Address and MAC Vendor.
Unlike similar tools, the report doesn't leave you to manually browse through a long list of IPs. There are hotkeys to step directly through open, dead or alive hosts, select hosts of different types and carry out actions on them: rescan, delete, export in various formats, more.
Right-clicking a host and selecting "Open" displays various ways you can explore or check that device further: Windows Shares, Web Browser, FTP, Telnet, Ping, Trace Route, Geo locate, E-mail sample.
The list of "Openers" can be customised to add other programs. If you'd like to open a copy of Chrome at a specific network address to use some extension you've installed, for instance, you can set that up in seconds.
Angry IP Scanner now proudly supports HiDPI/Retina screens on Windows and Linux starting with version 3.5 released today.
Mac OS X retina support was already available before.
This works thanks to an update in SWT (the GUI toolkit) to version 4.7M3, which in addition to scaled fonts now also scales images as well. Also, HiDPI versions of all icons was also provided, updating most of the icons to a flatter style.
Support for running with Java 6 is also now dropped, so that the last version compatible with Java 6 is 3.4.2. According to the statistics, there are a very few users still running Java 6. All of them are recommended to upgrade their Java.
Running on Windows XP is no longer officially supported, however it may still work. Angry IP Scanner now uses some Unicode characters in the UI that may not be rendered correctly by this version of Windows.
Angry IP Scanner delivers just about everything you'd want from a network scanner: it's fast, accurate, configurable and easy to use.