Flashcards: Understanding Port States and Network Security Techniques — 14 cards

Open|Filtered state — definition?

Indeterminate port status due to missing responses.

SYN proxy — role?

Intercepts SYNs, answers without revealing internal port info.

Firewall vs load balancer — function?

Firewall controls traffic; load balancer distributes it.

Nmap half-open scan — mechanism?

Sends SYN, analyzes responses to determine port state.

Port knocking — technique?

Sequence of connection attempts to open hidden ports.

Impact of NAT devices — effect?

Can obscure port states; SYN proxy masks true status.

TLS mutual authentication — process?

Both client and server verify identities via certificates.

Open|filtered — caused by?

Missing TCP responses due to network devices or proxies.

SYN proxy — how answers SYN?

Responds with SYN-ACK, delays internal responses.

Firewall/load balancer as proxy — effect?

Can cause ports to show as open|filtered in scans.

Nmap half-open — affected by proxies?

Yes, proxies can cause ambiguous open|filtered results.

Port knocking — purpose?

Hides services, opens ports after correct sequence.

NAT without SYN proxy — effect?

Does not typically cause open|filtered; ports are detectable.

TLS mutual auth — impact on scans?

No, occurs after TCP handshake, doesn't affect port responses.