Installing Internet Explorer 5 wipes out tunnelling

Installing Internet Explorer 5 wipes out tunnelling

The new Internet Explorer 5 from Microsoft has a bad habit of wiping out an important "tunnelling" feature that is used for secure communications across the Internet.

Fortunately, Microsoft has published a functional work-around. And it's a work-around that helps users of Netscape Navigator and Internet Explorer 4.0 too. So read on if you use any of these products.

"Tunnelling" is a way to encrypt communications between a server and a remote user. This keeps the information that passes between both points secure on a decidedly insecure Internet.

Microsoft refers to this as the Point to Point Tunnelling Protocol (PPTP) or virtual private networking (VPN). Using the Internet as a secure, private network (with the right security software) can save customers big bucks compared with using leased lines.

Tunnelling first became a feature of Windows 95 with the addition of an upgrade known as Dial-Up Networking (DUN) 1.2. It's now a standard feature of Windows 98 and NT 4.0.

The installation of Internet Explorer 5 seems to make worse a flaw somewhere in Microsoft's tunnelling protocol. BugNet, a Web site that follows PC products and their problems, performed extensive testing on IE 4.0, IE 5, and Navigator 4.51, and found that a few tweaks were needed to get tunnelling to work properly in many cases.

The following are BugNet's findings.

Running on Windows 95 and 98 clients, Navigator 4.51 and IE 5 had trouble opening Web pages on a server via tunnelling, until the Microsoft work-around (described below) was implemented.

Running on a Windows NT 4 client, Navigator 4.51 and IE 4.0 opened Web pages fine. But IE 5 wouldn't open Web pages on a Windows NT client via tunnelling without some tweaking.

Microsoft has acknowledged the problem with DUN in an article at (

A VPN connection may never be established if the properties of the connection show your VPN server's host name rather than its IP address.

For example, if your connection shows the host name, the connection will work better if you change it to an IP address such as (where 255 can be any value from 0 to 255).

If you don't know the IP address of your server, you can find it using Windows' Ping utility. At a text-mode prompt, type ping servername. The four-part number in square brackets is your server's IP address.

To change your host name to an IP address for your tunnelling connections, open My Computer, then open Dial-Up Networking. Right-click any VPN connection you may have (such as "Corporate Office", "WAN", or whatever) and click Properties. Type the desired IP address in the "Host Name or IP Address" box and click OK.

For more information on tunnelling and how to set it up, see Microsoft's Web site at (

BugNet found that this work-around fixed most problems with tunnelling. But it also found that PPTP filtering had to be turned off to get IE 5 to support tunnelling on NT 4.0 clients. For complete information on this topic, see (

IE 5 has also created some nasty problems for people who use Diamond video drivers for the graphics cards known as Viper V550, Monster Fusion Z100, and Monster 3D II. If you install any of the above drivers after IE 5, they overwrite IE 5's comctl32.dll file and your system won't restart.

If you've been bitten by this problem, you can salve your wound by extracting the correct .dll file from your Windows 95/98/NT CD-ROM. The complete procedure is in the IE 5 readme.txt, which is available at (

Diamond has released new drivers that do not have the problem.

Download from (

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