Digital Router Question:

An IDS is an Intrusion Detection System with two basic variations: Host Intrusion Detection Systems and Network Intrusion Detection Systems. An HIDS runs as a background utility in the same as an anti-virus program for instance, while a Network Intrusion Detection System sniffs packets as they go across the network looking for things that aren't quite ordinary. Both systems have two basic variants- signature based and anomaly based. Signature based is very much like an anti-virus system, looking for known values of known 'bad things' while anomaly looks more for network traffic that doesn't fit the usual pattern of the network. This requires a bit more time to get a good baseline, but in the long term can be better on the uptake for custom attacks.