Port scanning-security system-network security technology and protocols
port scan
Full TCP connection: three-way handshake
Semi-open scan: first two handshakes
FIN scan: no need to establish a TCP connection
Third-party scan:
Denial of service attacks include:
- Sync Packet Storm
- ICMP attack
- SNMP attack
They all modify the registry to defend against attacks.
Examine the principles of these three denial-of-service attacks
a
Information security assurance system and assessment methods
From low to high, there are five levels in total.
Autonomous protection level
. System audit protection level: finer-grained autonomous protection level
. Security tag protection level: mandatory access control.
Structured protection level: full-scale mandatory access control.
Access verification protection level: access monitoring. device
Just understand it
network security technology
Isolate internal and external networks
listening device
monitor, analyze
Not inspected
Cyber Attacks and Threats (Important)
Replay attacks and denial of service are often investigated.
Adding timestamps to information can solve replay attacks.
network security protocol
Focus on things above the transport layer
PGP: Secure Email Protocol
Just understand it (rarely take the test)
d
is supposed to be PGP, but it doesn’t
b
d
