Networking

2025-04-19

What is computer network? Why its useful?

How does internet works?

ping google.com - ping any site to check if its up and right

traceroute [google.com](http://google.com) - tracing the source

OSI Model →

  • Application (HTTP/HTTPS)
  • Presentation (Syntax/Security)
  • Session (API, Socket)
  • Transport (TCP)
  • Network(Packets)
  • Data Link (Ethernet)
  • Physical (Router/Cable)

For TCP/IP →

https://takeuforward.org/computer-network/explain-tcp-model/

IP/Subnets →

  • IPv4 - limited but most used → solution: create subnets (same IP for different devices connected to same router)
  • IPv6 - more than enough, but not much used yet

DNS / NAT / Firewalls →

Networks setting in AWS :

VPC (Virtual Private Cloud)

Subnets - (can be no preference)

auto-assign public-IP - enable

Firewall (security group) - can only access with SSH

security group name

image.png

How to set Domain Name →

For this we need a webpage, and for that we need nginx

sudo apt-get update

sudo apt-get install nginx

cd /var/www/html

systemctl status nginx - to check if nginx server is running (at port 80)

nslookup [google.com](http://google.com) - to show ip

instance → security → security-group → inbound rules → edit inbound → add rule → type(custom tcp) , port(80), source type(anywhere-ipv4) → save

NAT (Network Address Translation)

image.png

assignment : AWS VPC & VPC Peering Project for Devops & Cloud

VPC peering → connecting two VPCs

Load Balancer →

To distribute traffic

  • application load balancer
  • network load balancer
  • gateway load balancer