Network Security

Confidentiality keeps traffic private (encryption), integrity ensures data isn't altered in transit (hashing), and availability keeps the network reachable (redundancy, DoS protection).

Redundant links, redundant hardware (dual power, stacked switches), first-hop redundancy protocols, load balancing, and DDoS mitigation.

With cryptographic hashes or message authentication codes (e.g., HMAC); any modification in transit changes the computed value, so tampering is detected.

Authentication (prove identity), Authorization (what you may do), and Accounting (log what you did).

Authentication verifies who you are (credentials); authorization determines what you are allowed to access or do after identity is verified.

Who connected, when, for how long, and what they did — session logs and commands used for auditing and billing.