Nearly each application needs to have a well-designed GUI. Maybe it’s confusing, but the best application would not be accepted by clients when it has an ugly user interface. So next to colors and structuring it’s probably a good advise to have some well-designed icons in your application. When you search around you’ll find thousands of ‘free’ icons but in most cases they are outdated (WIndows 3.1 style) or only free for personal use, so you could not use them in your applications. I’ve found iconshow.de which offers currently more than 14.000 (!) icons. Of course this is not freeware but currently it’s 139,- € for all 14000 icons (prices might increase when new icons are added). Once you bought it you’ll get a lifetime update license so you will get all new icons for free! For me it was a good buy, definitely.

Network Monitor 3.1 is a free application that allows you to capture, display, parse, and save packets that are received by your network adapters. To parse packets, Network Monitor 3.1 applies knowledge of the structure of the various protocols to the hex data contained in the packets and displays the resulting interpretation.

Network frames contain information such as the address of the computer that sent the frame, the address of the computer to which the frame was sent, and protocols that exist within the frame. Network frames often contain data as well.

You can configure Network Monitor 3.1 to display specific types of information that are most relevant to you. And, to make analyzing the information easier, you can modify how information appears on the screen and you can filter or save the information for review at a later time.

See their blog for more information

Active Directory Explorer (AD Explorer) from SysInternals / Microsoft is a free advanced Active Directory (AD) viewer and editor. You can use AD Explorer to easily navigate an AD database, define favorite locations, view object properties and attributes without having to open dialog boxes, edit permissions, view an object’s schema, and execute sophisticated searches that you can save and re-execute.

AD Explorer also includes the ability to save snapshots of an AD database for off-line viewing and comparisons. When you load a saved snapshot, you can navigate and explorer it as you would a live database. If you have two snapshots of an AD database you can use AD Explorer’s comparison functionality to see what objects, attributes and security permissions changed between them.