Network

ARP(Address Resolution Protocol) is a protocol that finds the MAC address corresponding to an IP address. When communication occurs between devices on a network, it is necessary to find out the MAC address to deliver the packet to the destination. The Role of ARP Convert IP addresses to MAC addresses Identify devices that can communicate directly within the network Optimize performance through ARP caching Detect duplicate IP conflicts (using Gratuitous ARP) ARP Operation Process 1. ARP Request (ARP Request) When a host knows the destination IP address but not the MAC address, it broadcasts an ARP request to the network. ...

DNS (Domain Name System) is a system that translates domain names into IP addresses on the Internet. When a user tries to access a website by typing in its domain name, DNS translates it into the IP address of the corresponding server and facilitates the connection. Role of DNS Translate domain names to IP addresses Translate IP addresses to domain names (reverse lookup) Provide mail server information (MX records) Map multiple IPs for load balancing DNS Resolution Process DNS operates in a hierarchical structure and goes through the following steps: ...

The OSI (Open Systems Interconnection) 7-layer model is a conceptual framework that divides the process of network communication into seven distinct layers. Standardized by the ISO in 1984, it serves as the reference model for modern networks. Layer 7 - Application Layer The layer closest to the user, the Application Layer is where the user-facing applications we interact with operate. Key Protocols: HTTP: Web service communication FTP: File transfer SMTP: Email transfer DNS: Domain name resolution Practical Use Cases: ...

CIDR (Classless Inter-Domain Routing) was introduced to overcome the limitations of the existing class-based IP allocation. It allows flexible allocation of IP addresses as needed, preventing address waste. CIDR Notation and Structure CIDR represents the network bit count with the ‘/’ symbol followed by the IP address: 192.168.1.0/24 Network part: 192.168.1 (24 bits) Host part: Last 8 bits Available IPs: 254 192.168.1.0/25 Network part: 192.168.1.0 (25 bits) Host part: Last 7 bits Available IPs: 126 Relation with Subnet Mask CIDR prefixes correspond one-to-one with subnet masks: ...

Basic Structure of an IP Address An IP address is broadly divided into two parts: a ’network portion’ that distinguishes between networks, and a ‘host portion’ that identifies individual devices within that network. It’s similar to the address system of an office building. If ‘123 Main Street, New York City’ is the network portion, then ‘Suite 301, 3rd Floor’ is the host portion. Devices that share the same network portion belong to the same network. ...