Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

We have a problem in office when a user connects to our LAN without disconnecting from WiFi network he was previously on (a free WiFi provided by building owners). At a minimum, firewall log entries are cluttered with machine attempting to reach WiFi supplied DNS servers via fixed link. More of a threat is scenario when machine is hacked it can be used to bridge networks (public/private).

How to auto-disable wireless or auto-disconnect from it, if physical cable (ethernet) is plugged in?

share|improve this question

I dont know of any downloadable software, but many new laptops come with it pre-installed. Dell laptops have something called Dell Control Point, which is mostly a useless hassle, but does have a few redeeming qualities. One of which is the option to disable wireless when docked or plugged in.

share|improve this answer

You don't need it. Assign different IPs to these interfaces, and set a better metric to the wired connection's routes: it will become preferred, and while Wi-Fi is still online it is not used ;)

share|improve this answer
My problem is that nameservers from WiFi are still put in common list and machine unnecessrily queries wrong dns. Besides, wifi is autoconfigured and APs may vary – Konrads Nov 25 '09 at 11:25

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.