1. What are the parts of a URL and what are the functions of each part?

Uniform Resource Locator (URL)

(Photo from Hungry Man Valley)

Protocols such as HTTP/HTTPS indicate which protocols the browser must use.

The domain name, such as www.baidu.com, indicates which Web server is being requested.

Port The default HTTP port is 80, and the default HTTPS port is 443. When these two protocols are used, you do not need to display the specified port. The browser adds the port by default.

  • How do I know which port to use? Querying the Port List

For example, /s indicates the path of the resources on the network server

The query character string is as follows:? Wd =hello&rsv_spt=1 is an additional parameter provided to the network server. These arguments are lists of key/value pairs separated by the ampersand sign.

Anchors such as #5 refer to locations within the document that are not sent to the server and are not displayed in the Network panel. Sometimes anchors appear to be in Chinese, but do not support Chinese, converting Chinese into numeric symbols.

2. What is the function of DNS? How to use the nslookup command?

DNS The Domain Name System (DNS) is used to match Domain names with IP addresses.

  • How do I query the IP address corresponding to a domain name

    Run the nslookup command to query DNS records and check whether domain name resolution is normal. When network faults occur, the nslookup command is used to diagnose network faults.

    eg: nslookup baidu.com

3. What is the function of IP? How do I use the ping command?

  • IP functions:

  1. Locating a device

  2. Encapsulates data packets for communication with other devices

  • Using the ping Command

How do I get the server IP address? Eg: ping baidu.com

4. What is a domain name and what kinds of domain names are they?

A domain name can be said to be a proxy for an IP address, in order to facilitate the memory of the latter.

One domain name can correspond to multiple IP addresses (load balancing)

One IP address can correspond to different domain names (shared host)

  • What are the types of domain names:

  1. Category domain names (international domain names) a total of 7,.com(commercial companies); .NET (Network services); .org(organization association, etc.); .gov(government department); .edu(educational institution); .mil(military); .int(international organizations).

  2. Country domain name (geographic top-level domain name), a total of 243 country and region codes, for example. CN stands for China and.uk stands for the United Kingdom.

.com is a top-level domain name

Baidu.com Secondary domain name

www.baidu.com Is a third-level domain name. It is a subdomain name of Baidu.com. So www.baidu.com and baidu.com are two domain names. (It is possible that the secondary domain name and the tertiary domain name are not the same company)