can't connect to internet without turning off firewall

For the last few days, I cannot connect to the internet unless I turn off the firewall in Security. I suspect it is due to the latest OSX update after which the connection problem appears. Does anyone have the same problem? I connect using wifi via Airport Extreme Base Station which I hope protect me to some extent online. I don't want to go online unprotected. Can someone help?

Message was edited by: philosokat