Intrusion Protection System and Intrustion Detection System (IPS/IDS) devices are an important layer in the overall network security profile of any business. They provide a basic sanity check on traffic to and from your network that your firewall has deemed acceptable to pass. It’s part of the defense in depth initiative that any security conscious company should employ. Each layer is responsible for a particular security check. IPS/IDS units check traffic that has passed the basic access control list on the firewall for any potentially known bad payload. How they do this? Well, here is a basic understanding of IPS/IDS.