General

Windows Tips:
File Extensions and Network Traffic

We provide a neat little trick so let you display local network traffic in the Windows 2000 system tray, and show how to ensure all files are shown with their complete filenames.

by Jim Freund Managing Editor of CrossNodes, an EarthWeb site [March 4, 2002]

Here's a neat little trick you might find useful for your workstation, or that of some machines you administer.

No doubt you are familiar with the dial-up networking icon that lives in your system tray whenever you're online. Were you aware that could also be set up to display local network traffic?

To set this up in Windows 2000, bring up the Local Network Properties. To accomplish this,

1) either right-click on My Network Places or in the Start menu,

2) bring up Settings | Network and Dial-up Connections, and right-click on Local Area Connection.

3) In either event, select Properties from the mini-menu.

4) This will bring up the Local Area Connection Properties window, at the bottom of which is a checkbox next to "Show Icon in taskbar when connected" Select that, close everything, and you're done.

Now you'll see that friendly icon in the system tray blink with the incoming/outgoing data, with some limited stats for you to look at. Not exactly the most powerful traffic analysis tool at your disposal, but at least you'll know at a glance that there is connectivity, and it's not just that your machine isn't responding.

Viewing all file extensions
One trick that several creators of viruses and other forms of malevolent code try is to make an e-mail attachment appear to be something other than what it is. Window's default is to hide file extensions, and therefore it is a common exploit to use two file extensions to spoof users into believing the attachment is benign, and something other than what it truly is. For instance, a file that is truly named FILENAME.DOC.EXE would show up in Windows as being a Word document. Double-clicking upon it, though, will launch you into Trojan hell.

Therefore it is a wise precaution to make sure that all of your machines display all files, and with their complete filenames.

• open Control Panel
• From the "View" menu, select "Options..."
• Win 2K/XP: select Folder Options
• Click on the "View" tab
• Make sure both "Hide files of these types" and "Hide file extensions for known file types" are unchecked
• Make sure "Show all files" is checked.
• Win2K/XP: Make sure "Hide protected operating system files" is unchecked
• Click "OK" to save changes

Another step is to change the Registry settings.

• Run regedit
• From the Edit menu select Find
• Under "Look at", uncheck the "Keys" and "Data" entries and ensure the "Values" entry is checked
• Enter "NeverShowExt" in the "Find What" box and click "Find Next"
• When a value is found, right click on the value name and select "Delete"
• Press F3 to find the next occurrence of "NeverShowExt" and repeat the procedure until all occurrences of "NeverShowExt" have been deleted.
• The computer will need to be rebooted for changes to take effect

As always, be aware that changes to the Registry are dangerous. We strongly advise that you back it up before proceeding with any manual registry changes.

Run regedit, click on Registry, and select "Export Registry File". Choose a safe location; preferably a network directory and save the file.

—End