In other words, having systems in place beforehand which prevent attacks before they begin.
Related to the first definition, having peace of mind knowing that your systems are safe and protected.
This includes contingency plans for what to do when attackers strike, keeping up with the latest CERT advisories, hiring network security consultants to find insecurities in your network, etc.
Why good? Because it lets you filter what comes in and what goes out. Why bad? If that point goes down, you are cut off from everyone else. Also, may have lots of congestion at that one point.
Forge source IP so that the victim can’t figure out who you are.
Alice can send a RESET
Malicious user can send a virus to the trusting web client, instead of the program they thought they were downloading.
Security techniques: IDS can be configured to look for internal inconsistencies in traffic patterns Firewalls can be configured to block off one part of a corporate network from another part to further restrict access Can also use hardware based identification tokens with strong encryption to identify who is doing what