Networking

Networking

• IP address is a 32 bit value
• every 8 group denote an octet seperated by a .
• So Ip address range from 0.0.0.0 to 255.255.255.255

Switch

• Sits within the LAN
• Faciliates the connection between all the devices within the LAN

Router

• ip address of the router is nothing but the gateway
• while the switch lets one device communicate with the other within a network the router helps to communicate over globally

Subnet (How to know whether the device is in or outside the LAN)

• Devices in the lan belong to the same ip address range

255.255.0.0 — means 24 bits are fixed 255.255.255.0 —- means that 16 bits are fixed

• Value 255 fixates the Octet
• Value 0 means free range

A short way of writing this subnet is called as the CIDR range CIDR = Classless Inter-Domain Routing Eg : 192.168.0.0/16 or 192.168.0.0/24 where the /16 and the /24 represent the bit that are fixed

Network Address Translation

NAT is used in the routers, when the user sends a request to outside world then the router converts the ip into a public ip and the response which comes from the public ip is converted back into the private ip and sent back to the user.

Firewall

Protecting a network from unauthorized access

@ PORTS

• ports are like a multiple doors to the building
• there are default ports for many applications

DNS (Domain Name Service)

• Translates domin names to ip addresses
• top level domains
• .edu .ml .com .org .net .gov
• geographical domain like .in .de etc….

Networking Commands

ifconfig

netstat   - shows active connections or ports used by the applications in computer

ps aux   - resources used by applications

nslookup   -  to get the ip  address of any domain

ping   -- to check whether an addreess or application is accessible or not