Avast! Internet Security 2014.9.0.2016 - Firewall blocks Hyper-V Internet trafic

Hi,

Since I installed Avast Internet Security (Windows 8.1) all my Hyper-V virtual Machines (either Windows or Linux) have partially lost their internet connection. Stopping the Avast Firewall brings the connection back to normal behaviour.

I said “partially” because I’m sure that some traffic is allowed, actually from any VM a “tracert” to any internet address (ie, tracert www.google.com) resolves the name and finds the destination as expected. However, the browsers (I have tried IE, FireFox, …) can’t find any page. (Remember: stopping the Avast Firewall brings the Internet connection of all my VM’s back to normal behaviour)

Any ideas, please?
U.S.

Solved!

Did you need to allow ICS mode