Finally understand the difference between TCP and UDP protocol

1. What is the function of header checksum in IPv4 data header? ② Why does the header checksum fail to resist IP source spoofing? ③ The solution to IP source address spoofing is given.

A: What is the function of header checksum in IPv4 data header? The checksum field is used to check whether the header part of the IP datagram has changed during transmission to the receiving end, and to check the integrity and correctness of the IP header.

② Why does the header checksum fail to resist IP source spoofing?

According to the definition of IP spoofing and the figure above, IP spoofing is the process of falsifying the datagram header so that the information displayed is not from the actual source, as if the packet was sent from another computer. The header checksum is used to check the integrity and correctness of IP headers. Since the hacker forged the source address, the sent datagram looks like it was sent from another one, so the source IP address in the IP datagram is not trusted, so it is not possible to detect whether the source IP address is spoofed.

③ The solution to IP source address spoofing is given. (1) The firewall can identify IP source address spoofing and can use the firewall to detect it. (2) Take stronger certification measures in the target equipment &#