Network & Email · page 17

Infers hop distance and initial TTL from TTL values.

Explains handshake fields from pasted s_client output.

Breaks IANA cipher suite names into key exchange, cipher, and MAC parts.

Tables TLS versions with deprecation dates and browser cutoffs.

Decision tree for incomplete chain and untrusted root errors.

Compares OCSP, OCSP stapling, and CRL checking flows.

Explains TCP states with likely causes like SYN flood signatures.

References ss flags and filter syntax with examples.

Plans tuning for TIME_WAIT pileups on busy frontends.

Explains CLOSE_WAIT leaks and application-level shutdown bugs.

Plans port ranges and exhaustion alerts for outbound-heavy hosts.

Explains CRC, runts, giants, drops, and carrier counters.

Explains ip route output lines, metrics, and scope fields.

References ip(8) subcommands for links, addresses, routes, and neighbors.

Explains speed, duplex, pause, and offload flags from ethtool output.

Compares bonding modes 0 through 6 with switch requirements.

Decodes 802.1Q header bytes from pasted hex into VLAN and CoS.

Maps late collisions and CRC symptoms to duplex mismatch causes.

Steps broadcast storm containment from ports to STP checks.

Diagnoses which DISCOVER, OFFER, REQUEST, or ACK step fails.

Builds DF-size ping commands for Windows, Linux, and macOS.

Builds the hex wake payload from a target MAC address.

Triages block errors, timeouts, and option negotiation failures.

Compares active versus passive ports and NAT impacts.