U2.3 TCP, Routers, VLAN

TCP vs UDP
1. TCP
  1. connection oriented
2. UDP
  1. connectionless
TCP handshake
1. 1. node sends packet with SYN flag set
  1. 1.1 receiving node puts entry in its connection-half-open table for sending node
2. 2. receiving node replies with a packet that has both SYN and ACK flags set
3. 3. sending node responds with a packed with the ACK flag set
  1. 3.1 receiving node removes entry for sending node from its connection-half-open table
4. RFC 793
5. 4. parties are ready for communication
Denial of Service
1. SYN flood attack
  1. 1.Attacker sends many SYN packets to receiving node.
  2. 2. Receiving node adds requests to half-open-connection table.
  3. 3. Attacker does not send ACK packet.
  4. 4. Receiving node's table gets full. Cannot process anymore connections.
  5. IP source address can be spoofed for a more effective attack.
router
1. connects and allows communication between networks
  Anlagen:
  - U2.3 TCP, Routers - Router Diagram
2. routes packets in one of 3 ways
  1. 1. direct delivery of a packet to a directly connected device
  2. 2. indirect delivery of a packet by forwarding the packet to a default router
  3. 3. next-hop delivery of a packet over a known route by forwarding to the next hop router
3. Layer 3 device
VLAN
1. virtual local area network
2. a switch's ports are split up so that logically there is more than one local area network configured
  1. subnets - VLANs set up on one switch
3. VLANs are not meant to be a secure means of separating LANs.
network vulnerability summary
1. ARP spoofing
2. MAC flooding
3. SYN floods
4. IP Spoofing

Nächster

U2.3 TCP, Routers, VLAN

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