Computer network interview questions (application layer)
The concept, use and implementation algorithm of DNS query in DNS
- concept
- Domain name resolution, conversion of www.xxx.com to ip, can make users more convenient to access the Internet, without having to remember the ip address that can be directly read by the machine
- The DNS protocol runs on top of the UDP protocol, using port number 53
- The order in which the host resolves the domain name o
- Browser cache
- Find the local hosts file
- Route cache
- Find a DNS server (local domain name, top-level domain name, root domain name)
- Iterative query, recursive query
http basic format
HTTP request:
HTTP response
The difference between Cookies and Session
- A cookie is a text string handle sent to the client ’s browser and stored on the client ’s hard drive, which can be used to persist data between sessions of a certain WEB site. session actually refers to the visitor ’s arrival The time until the homepage leaves. Session actually uses cookies for information processing. When the user first makes a request, the server creates a cookie on the user's browser. When the session ends, it actually means that the cookie has expired. 3. cookie data Save on the client, session data is saved on the server
The difference between GET and POST
| Operation method | Data location | Plaintext ciphertext | Data Security | Length limit | Application scenario |
|---|---|---|---|---|---|
| GET | HTTP header | Plaintext | Unsafe | Small length | Query data |
| POST | HTTP body | Can be understood | Safety | Support large data transmission | change the data |
Steps through a complete HTTP request
You can also refer to the article: "Capture the actual combat | How is the HTTP request in the browser completed? 》Https://mp.weixin.qq.com/s/_fB7r53BGZRvpG9YAPRQ8A
The difference between http2.0 and http1.1
