I, too, am having wifi issues with Jessie on my RPi3. If I connect via Cat-5 between eth0 and my router Internet access works just fine. However, if I attempt to use wlan0, I get no connectivity. My router uses WPA/WPA2 for security, and all other wifi devices at home (e.g., phones, tablets, laptops, desktops, printer and RPi Wheezy on RPi2) connect and operate just fine.
I tried a couple of months ago to make this work, and I was told the only solution wasto get rid of WEP and upgrade to WPA. Done (painfully). Still not working for RPi3 with Jessie. I have observed via ifconfig, et al, that both interfaces appear to be set correctly (IP, Netmask - 255.255.255.0, etc.). However the wifi icon reports
" eth0: Configured 10.10.10.112/24
wlan0: Associated with mywifihub
wlan0: Configured 10.10.10.106/8"
The wired connection yields full Internet access (DNS, WWW, etc.) while my browser reports:
"Oops! It was not possible to show this website
The website at http://www.abc.com
seems to be unavailable. The precise error was:
Could not connect: Network is unreachable"
If I plug the Cat-5 back in everything works again. I have need for a wifi-based solution, and it is not possible to run a cable to this computer. It appears that the wifi is picking up the wrong netmask (/24 vs /8) or not setting the correct path to the router, or more.