Ever heard about ARP spoofing or man in the middle attacks? If not then this may not be for you, but if on the other hand “Yes” then here is a tool for you..
Our pal Irongeek has released this nifty small util “DecaffeinatID:” that will sit in your tray until it detects something nasty going on (like eg. attempted ARP spoofing of your default gateway) and then raise hell and bells to warn you.
Basically what it does it to monitor the MAC address of your default gateway, if this for some reason changes (which it never should) you will be warned and can take precautions.
Besides this ARP ‘shield’ the util offers a few other nifty security tricks, anyway check it out at;
http://www.irongeek.com/i.php?page=security/decaffeinatid-simple-ids-arpwatch-for-windows