Ubuntu 12.04 - how can i have eth0 and wlan0 both active where eth0 is primary and wlan0 is just for internet browse

Question

I have a box running Ubuntu 12.04. There i have eth0 which is used as local network no internet. But i have also in that same box wlan0, and WiFi availability.

Now how can i have both interface active? So that eth0 remain as it is, but wlan0 also get auto active to specific WiFi as fixed. When ever internet inbound/outbound access requires, i want to use wlan0 interface, not the eth0 interface as it is used already for webservice in local networks.

Any ideas how to achieve this? ( i tried this but not working for both interface https://help.ubuntu.com/community/WifiDocs/WiFiHowTo )

Solution

It sounds like your eth0 interface is routed to your local network, while your wlan0 interface is routed to the outside world. Consider establishing routes for your two interfaces as shown at this answer.

For more information about routes, visit this page at The Linux Documentation Project.