1. Basics of Networking
- NETWORK — Collection of computers and devices connected together for communication & data exchange between them.
- NODES — Devices connected to the Network. Includes computers, servers, printers, routers
- Protocols — Set of rules and standards how data is transfer over network like TCP,HTTP,FTP
- LAN (LOCAL AREA NETWORK) — Network that covers a very small area
- WAN (WIDE AREA NETWORK) — Network that covers a wide area like city, country.
- IP Address — Unique Numerical Id for every device on network
- Firewall — Monitor and control the inbound and outbound network traffic
2. IPv4 and Subnetting
IPv4 = Internet Protocol version 4
- It uses 32 bit address. It has both public and private IP’s. Starts from 0.0.0.0 to 255.255.255.255 approx 4 billion ip address. Inthat 18million address are private.
10.0.0.0 — 10.255.255.255 — (24 bit) Class A — 1,67,77,216
172.16.0.0 — 172.31.255.255 — (20 bit) Class B — 10,48,576
192.168.0.0 — 192.168.255.255 — (16 bit) Class C — 65,536
Subnetting
- It is a Network inside the network (dividing larger network into smaller)
- To improve Network performance and security subnets are used.
3. FIREWALL
- It’s a Network Security Device that monitors and filters inbound and outbound network traffic.
- Firewall is the first line of defence in network security.
- It can be Hardware, Software, Software as a Service (SaaS), Public Cloud , Private Cloud (virtual)
TYPES OF FIREWALL
- PROXY FIREWALL — Filter network in Application layer ,Gateway from one network to another.
- PACKET FILTERING — Control data flow
- STATEFUL INSPECTION — Allow or Block Network traffic based on state,port and protocol
- Next Generation Firewall — Deep pocket Inspection, intrustion prevention
- UTM (Unified Threat Management) — Capabilities of stateful inspection, Intrustion Prevention and antivirus in a loosely linked manner
- Thread Focused — Advanced Threat detection.
4. Inbound and Outbound rules in Firewall
INBOUND — Protect Network against incoming traffic
OUTBOUND — Project against outgoing traffic
5. DHCP Server
- DHCP — Dynamic Host Configuration Protocol
- It maintains a unique IP address for a host using the server
- DHCP also provide DNS(Domain Name System) server
- DHCP port numbers used for servers and clients are 67 and 68 respectively
6. DNS Server
- Domain Name System (DNS) is the Phonebook of the Internet
- Four servers work together to deliver IP address to the Client
- DNS Caching — The recursive resolver store the information for a limited amount of time. Meantime host hit the same server instead of doing the domain lookup process, simply respond to the client instantly
- Recursive Resolver
- Root nameservers
- TLD nameservers — Top Level Domain
- Authoritative nameservers
7. Cloud Flare and How to Use
- Cloud Flare — Its a large network of servers that can improve the Security, Performance and Reliability of anything connected to the Internet. Cloud flare is the Content Delivery Network by providing Edge locations.
- Performance Improved by providing the Edge Locations. Example: If a cloud flare customer’s server is in USA, if the client access the server in Europe cloud flare provides their servers to reach the client without latency
8. DNS Records
- Provides Information about a domain including what IP address is associated with the domain. DNS Records also have TTL (Time to Live) defines how often DNS Server clear the records
TYPES OF DNS RECORD:
- A record — Holds IP Address of the Domain. (IPv4)
- AAAA record — Holds IPv6 Address
- CNAME record — CNAME (Canonical Name) map one domain to another
- MX record — Directs mail to an E-mail server
- TXT record — Store text in records
- NS record — Store Name Server for DNS entry
- SOA record — Stores Admin Information
9. Point DNS Records
- Connecting DOMAIN NAME to the Web Host Server
- Pointing is the one last steps before server goes live
10. How to Secure Network
- Network Access Control — Only Authenticated and trusted endpoint devices can get into the system.
- Firewall Security — Monitor and filters the incoming and outgoing network traffic. It follows defined rules of IP address and ports to allow or deny traffic
- Intrusion Prevention System (IPS) — Identify and Prevent unusual network traffic. Its does not follow any static rules like firewall but actively analyze, learn and create rules. EXAMPLE: If Firewall is your Building Security Gate, IPS is like your security guard behind the gate
- Security Information and Event Management (SIEM) -It sends out reports on security-related events like failed logins and sends out alerts if its analysis indicates a potential security issue
