IP Addresses

IP addresses are unique identifiers assigned to devices on a network to enable communication.

What are IP Addresses?

IP addresses are unique numeric identifiers assigned to devices on a network that enable communication between them.

Types of IP Addresses

IPv4

  • Format: 32 bits (4 octets)
  • Example: 192.168.1.1
  • Range: 0.0.0.0 to 255.255.255.255
  • Classes: A, B, C, D, E

IPv6

  • Format: 128 bits (8 groups)
  • Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
  • Notation: Hexadecimal
  • Characteristics: Larger address space

IPv4 Classes

Class A

  • Range: 1.0.0.0 to 126.255.255.255
  • Mask: 255.0.0.0 (/8)
  • Networks: 126 networks
  • Hosts: 16,777,214 hosts per network

Class B

  • Range: 128.0.0.0 to 191.255.255.255
  • Mask: 255.255.0.0 (/16)
  • Networks: 16,384 networks
  • Hosts: 65,534 hosts per network

Class C

  • Range: 192.0.0.0 to 223.255.255.255
  • Mask: 255.255.255.0 (/24)
  • Networks: 2,097,152 networks
  • Hosts: 254 hosts per network

Special Addresses

Private

  • Class A: 10.0.0.0 to 10.255.255.255
  • Class B: 172.16.0.0 to 172.31.255.255
  • Class C: 192.168.0.0 to 192.168.255.255
  • Usage: Internal networks

Public

  • Range: All other addresses
  • Usage: Internet
  • Registration: Registered in RIRs
  • Assignment: Assigned by ISPs

Special

  • Loopback: 127.0.0.1
  • Broadcast: 255.255.255.255
  • Multicast: 224.0.0.0 to 239.255.255.255
  • Link-local: 169.254.0.0/16

Subnetting

Concepts

  • Subnet: Network division
  • Subnet mask: Subnet mask
  • CIDR: Classless Inter-Domain Routing
  • VLSM: Variable Length Subnet Masking

Example

Network: 192.168.1.0/24
Subnet 1: 192.168.1.0/26 (64 hosts)
Subnet 2: 192.168.1.64/26 (64 hosts)
Subnet 3: 192.168.1.128/26 (64 hosts)
Subnet 4: 192.168.1.192/26 (64 hosts)

Address Assignment

Static

  • Manual configuration: Manual assignment
  • Advantages: Full control, predictable
  • Disadvantages: Manual management, errors
  • Usage: Servers, critical devices

Dynamic (DHCP)

  • Automatic assignment: Automatic assignment
  • Advantages: Automatic management, flexibility
  • Disadvantages: Less control, dependency
  • Usage: Workstations, mobile devices

Tools

Basic Commands

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# View IP configuration
ipconfig /all

# Ping address
ping 192.168.1.1

# Traceroute
tracert 8.8.8.8

# Nslookup
nslookup google.com

Network Tools

  • Wireshark: Packet analysis
  • Nmap: Network scanning
  • Tcpdump: Packet capture
  • Netstat: Network statistics

Best Practices

Design

  • Planning: Plan assignment
  • Documentation: Document assignments
  • Reservation: Reserve addresses
  • Scalability: Plan growth

Security

  • Segmentation: Segment networks
  • ACLs: Implement ACLs
  • Monitoring: Monitor traffic
  • Auditing: Regular audits

Maintenance

  • Inventory: Maintain inventory
  • Documentation: Document changes
  • Monitoring: Monitor usage
  • Optimization: Optimize assignment

References