Computer Network: Packet Capture architecture, computer network architecture

Computer Network: Packet Capture architecture, computer network architecture

Hold the winter vacation tail, 2.28, update a wave.

Packet Capture principles include network principles and underlying principles

1. network principle:

1) local environment-directly capture the incoming and outgoing traffic of the local NIC: Install ws directly on the terminal, and then capture the traffic of the local Nic to communicate with the Internet.

2) Hub environment (old network)-hub: flood traffic to all other ports and capture packets in the LAN.

* A hub (multi-port signal amplification device) is a hardware-only underlying device. It basically does not have the "smart memory" and "Learning" capabilities similar to switches. It does not have the MAC address table of the vswitch, so it does not send data in a targeted manner, but uses broadcast to send data. That is to say, when it wants to send data to a node, it does not directly send data to the target node, but sends data packets to all nodes connected to the hub.

3) vswitch environment:

* Port image (security): The SPAN technology that copies data packets from other ports to specific ports.

** ARP spoofing (attack): The arp spoofing software must be installed. Due to misplacement spoofing, PC1 continuously sends an arp table that is spoofed into pc2. an incorrect binding will be generated, the switch will throw data packets to pc1.

* ** MAC flood: a large volume of garbage packets are used to generate a large number of mac addresses. The original mac address table of the switch is changed, so that the traffic is routed to F1.

2. underlying principle: wireshark's underlying packet capture tool.

The above is the architecture of this packet capture tool.