System Design Life Cycle

This weekend I read through a good portion of Chapter 1 in the Cisco IINS book regarding the System Design Life Cycle (SDLC) and how to create a security policy. I played around with a low-level network scanner tool called Nmap. It's pretty cool, it can scan various things in your network such as UDP/TCP ports and can even graph a simple network topology out of it! I also played around with Cisco's security policy creator template which creates a ready to go security policy with pretty much everything you need. Starting this week I'm going to begin really digging into my studies work and weather permitting. I'm honestly not sure if I'll sit this exam but i do want to up my knowledge on security, even if it's just general knowledge.