What have you experienced after visiting the Baidu web page once? Disclosure of https and tcp protocols

What does it take to open a https://www.baidu.com/ page with a simple action? Do you want to explore the internal principle? Then let's explore together.

1. Preparatory work

Install wireshark. Wireshark (formerly known as Ethereal) is a network message analysis software. The function of network packet analysis software is to capture network packets and show the most detailed network packet data as much as possible. Wireshark uses WinPCAP as the interface to exchange data messages directly with the network card.

two。 Grab message

Open wireshark, turn on listening mode, open the browser, type https://www.baidu.com/, wait for return, close the browser, finally stop wireshark listening, and save the file.

3. Analyze message

3.1View the address of Baidu, cmd command line nslookup

C:\ Users\ dell > nslookup www.baidu.com

Server: ns-pd.online.sh.cn

Address: 202.96.209.133

Non-authoritative response:

Name: www.a.shifen.com

Addresses: 115.239.210.27

115.239.211.112

Aliases: www.baidu.com

Copy the code

As you can see from the above, the first person to visit the DNS server is the last article.