client-server-model

Table of Contents

Server Model

Client Server Model

Clients

A client is something that queries servers.
e.g. A browser, or mobile device

Servers

A server is something that responds to requests.
e.g. a Website backend

Networking

Making a GET request

When a browser looks up a website, it does a DNS lookup of the URL to find its IP Address
a DNS query goes to a set of servers, and the server returns the IP address.
an IP address is a unique id for public computers.
an IP address is like a mailbox for a computer.
dig domain makes a DNS query.

Server Response

With the IP address, the HTTP server knows where to send its request.
The client can then send messages to it, and the server can respond to those messages with its own messages.
HTTP is over TCP/IP, which is normally on port 80.
HTTPS is over TCP/IP with TLS, which is normally on port 443.

Exercise

Use nc -l 8081
- This listens on port 8081
Use nc 127.0.0.1 8081 to connect to port 8001.
- This connects to the client on port 8081.
  - Send messages to see them on both terminals.

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