Beyond FOSS built-in security

As explained earlier, no single device or method can help you achieve 100 per cent security. Also, it is important to note that for some attacks such as packet sniffing, packet crafting, etc, there are no built- in security features available in an open source distro. All the methods explained here surely strengthen security, but they must be complemented with commercial- grade appliances and devices, to design a robust perimeter defence system.