WinPCap is a Windows installable driver which allows applications to capture packets from the network (and therefore this unencrypted network traffic is in plain view). It typically requires the network card to be in "promiscuous mode", so that it receives network packets regardless of their intended destination(s). When this driver is installed on a computer, then the local users potentially can capture network packets from other users on that particular local computer. This is considered a security problem. However, I could not yet find any other security problems with this driver, such as a risk from users across the LAN or from the internet.

This driver is especially useful to DOSBox users who have the patch for the virtual network card, the NE2000. To provide for additional protection while using this setup, I attached helper scripts (batch files) to turn on or off the WinPCap driver while logged in as a regular user. First, install WinPCap 4.1.3 without enabling the load-driver-at-boot option. This should leave the driver off until the administrator loads an application using this driver; Instead, I included a batch file which will detect whether the driver is loaded or not, and if not, then it will load the WinPCap driver. Next, the DOSBox+NE2000 configuration can be started with potential access to the outside network (and internet). After use, then the other batch file is run to unload the driver while logged in as a regular user. There is basic error checking in the batch scripts and also they will request the administrator account username and password, so that there is permission to load or unload this driver which is at the kernel level of the operating system. These two batch files are in plain text so they can be easily viewed and edited.

I hope this will encourage use of the NE2000 patch, especially if running Windows 95 or 95/OSR2 in Daum's Build. I do not have a list of DOS games which would find this setup of advantage over using IPX.