kk

Why do we need an operating system

- Manages hardware components - Sits between hardware and application - User interface (GUI AND command ui) - File management

Ntp

123

SNMP

161 162

FTP

20, 21

SSH

22

Telnet

23

SMTP

25

RDP

3389

HTTPS

443

DNS

53

DHCP

67 68

HTTP

80

tcp

A connection-oriented transport layer protocol. more secure

Stages of DHCP

Discovery find dhcp server Offer dhcp offers ip Request : aks to use it Acknowledge: leases ip

ICMP is on what layer and what does it do ?

Internet control message protocol 3rd layer Ping our trace route to figure out connectivity issues

What is the core of an operating system?

Kernel

Which OSI layers happen in network

Lower 1 2 3 4

Layers of OSI

Physical data link network transport session presentation application

TCP handshake

SYN SYN ACK ACK

Which OSI layers happen in host machine

Upper 7 6 5

OSI stands for?

open system integration model