TCP/IP layer 4 application model
- Application layer (HTTP, DNS,FTP,SMTP,TELNET)
- The transport layer (TCP, UDP)
- The Internet layer (IP, ICMP, ARP, RARP)
- Network Interface Layer (various physical communication network interfaces)
Information transmission structure diagram between two terminals
IP(Protocol for interconnection between networks)
- The most commonly used IPv4 networks use 32-bit decimal addresses, such as 192.168.0.0
- 127.0.0.1 native
- 192.168..Small LAN
- 10..* Internal LAN (within the company)
- Other Wan
In IPv6, because of the number of IP addresses, 128-bit addresses (16 bytes) are represented by four hexadecimal bits
- 3ffe:2012:1015:cffe:1978:de123:12313:defe
Transmission Control Protocol
- A reliable connection between two points
Application layer DSN domain name resolution system
- On the Internet, domain name and IP address are one to one, but it is not easy to remember, domain name is better to remember, but the machine only recognize IP, so this is our domain name and IP conversion between the role
FTP (File Transfer Protocol)
- It is used to control the bidirectional transmission of files over the Internet
HTTP(Hypertext Transfer Protocol)
- Stateless, independent of each request
- request
- response
Request the request
Security, idempotence, caching
Idempotence, if you do the same thing multiple times, you get the same result
The response response
- 200 success
- 301 permanent redirection (IP change)
- 302 Temporary Redirection (TEMPORARY IP change)
- 403 Resources are not available. There are many cases. The common case is a pass-parameter error
- 404 page not found
- The 500 server is down
- 503 come back later
The web server
- Only static web pages can be deployed
Application server
- Dynamic web pages can be deployed
The two are often used together; When the Web server cannot find the content, it goes to the application server
- Apache can run on Linux, Windows, MAC
- Iss is owned by Microsoft and only available on Windows
- Nginx on Linux and Unix
that’s all