1. Networking and firewall
Presented by
Jeevan isnovar P
Yaltech Consultancy

2. Agenda
Network
Network Devices
IP Address
Network Commands
Firewall

3. Wht is Network?
A Network is a interconnection of Computers and peripherals devices on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wirelessly through radio waves.
Two kind of nodes are
End Devices
Connecting Devices
Medium

4. Types of Networking
There are two types of networking like wire and wireless connections
There are different range of networks

5. Network Topology’s Six type of topology's are 1. Bus 2. Star
Node’s are Geographically connected in network
Six type of topology's are
1. Bus
2. Star
3. Token Ring
4. Ring
5. Mesh
6. Tree

6. Network Cables
Networking cables are networking hardware used to connect one network device to other network devices or to connect two or more computers to share printers, scanners etc.
Different types of network cables, such as coaxial cable, optical fiber cable, and twisted pair cables, are used depending on the network's physical layer, topology, and size.

7. Network Nodes Computers and peripherals.
Connectivity devices are Hub, switch, bridge, router ,modem and repeaters.
Hub it’s a center point of network and that’s sends data to all nodes

8. Switch It’s a advanced model of hub and it’s intelligence device.
There are two models (Unmanaged switch, Managed switch ).
Layer two device and use MAC address.

9. Router
A router is a networking device that forwards data packets between computer networks.
Routers perform the traffic directing functions on the Internet.
Layer three device and use IP Address

10. Example of Router Connections

11. Modem
A modem (modulator-demodulator) is a network hardware device that modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information.
Layer two device

12. Comparison Chart Router Switch Modem Layer 3 Layer 2
Without modem will not connect internet
Use internal network
Directly connect to modem without router
Fast Routing Decisions
Take more time for complicated routing decisions
Depends on
LAN and WAN
LAN
NAT No

13. Gateway
This is a node which we able to use the entry point of internal network like modem and routers.

14. MAC Address
 Media Access Control, address is a globally unique identifier assigned to network devices, and therefore it is often referred to as hardware or physical address.

15. Internet Protocol (IPv4)
This is numerical label for finding the nodes each node have unique address in the internal network.
The range of systems are 0 to 255 and five class in overall IPV4 Networks
Class
Range
Private IP address
Numbers of Hosts in One Network
Class A
0-126 –
16,777,214 (254^3)
Class B
65,534 (254^2)
Class C
254 (254^1)
Class D
Multi cast
Class E
Research

16. SubNet Mask
An IP address has two components, the network address and the host address. A subnet mask separates the IP address into the network and host addresses (<network><host>).

17. Select properties of IPv4
How to set IP?
Start |
Control panel
Network & Internet
Network Sharing
Ethernet
Properties
Select properties of IPv4

18. Private and Public address
Public address are issued by ISP (Internet Service Provider ) and it’s unique.
Private address are used in internally.

19. Network Address Translation
The network address are translations between public and private networks.

20. Summary of Network

21. Network Commands
getmac − Displays the MAC addresses for your network cards.
hostname – Prints the hostname or computer name.
ipconfig − Display and change your TCP/IP configuration settings, or to
flush DNS or renew DHCP leases.
nbtstat − Displays protocol statistics and current TCP/IP connections using NetBIOS over TCP/IP.
net − A set of commands for interacting with Windows network functions.
netsh − Powerful utility that can adjust many network and interface settings.
netstat − Displays immediate networks stats, such as open ports and routing table information.

22. Cont. nslookup − For testing and troubleshooting DNS servers
pathping − Used for network troubleshooting.
ping − Used for simple network troubleshooting.
route − Manipulates network routing tables.
tracert − Helps identify connectivity problems between the local computer and a network address and Helps troubleshoot network connections by tracing the route to a server.

23. IP Config

24. Netstat

25. Netstat Cont.

26. Firewall
A firewall is a Hardware device or software that provides a layer of security into a network or computer.
Its primary task is to only permit traffic that is required to pass through and block all other traffic.
There are two type of rules inbound and outbound rule.

27. Firewall Hardware

28. Firewall Logic’s
1. Packet filtering or packet purity   Data flow consists of packets of information and firewalls analyze these packets to sniff out offensive or unwanted packets depending on what you have defined as unwanted packets.
2. Proxy   Firewalls in this case assume the role of a recipient & in turn sends it to the node that has requested the information & vice versa.
3. Inspection   In this case Firewalls instead of sifting through all of the information in the packets, mark key features in all outgoing requests & check for the same matching characteristics in the inflow to decide if it relevant information that is coming through.  

29. Firewall Rules Domain names Protocols Ports Keywords Example rule’s
Block port no 21
Add port no 80
Block domain
Block keyword “hack”