>Of course you can detect a sniffer, but are you willing to pay the cost >of doing so? More importantly, have you managed your security risks taking into account the possibility of being sniffed? Fixing holes is one thing. In some environments, this is a reasonable security solution (An example is many academic environments where there really isn't much in the way of sensitive data). In others, where data processed on computer equipment on a network is more sensitive (like trade secrets), if you didn't design strong authentication and encryption into your total security solution (thus making sniffers not really a threat), it's your own fault if a sniffer on your network intercepts data. -Craig