I have seen many forums saying that Ubuntu is virus free and it has no need for any firewall. Also it says that linux based distros do not need antivirus as there are only 40 virus around the world for linux. Out of those 40 virus only 3 are criitical and rest were developed in labs for testing.I have a original CD of Ubuntu and hence I installed it. It seems to work fine with all repositories updated. But is Ubuntu safe?