Default Gateway

Created: 2025-11-25 Tags: networking gateway routing fundamentals

Description

A default gateway is a router that connects a local network to other networks or the internet. It serves as the exit point for traffic destined outside the local subnet.

Key Concepts

Function

• Routes traffic to destinations outside local network
• Acts as intermediary between subnets
• Forwards packets to appropriate next hop
• Usually the first usable IP in a subnet

Typical Configuration

Network: 192.168.1.0/24
Gateway: 192.168.1.1
Devices: 192.168.1.2-254

How It Works

Local Device (192.168.1.10)
    ↓
Is destination on local subnet?
    No → Send to Default Gateway
    Yes → Send directly
    ↓
Default Gateway (192.168.1.1)
    ↓
Routes to destination network

Security Considerations

• Gateway can monitor all outbound traffic
• Single point of failure
• Target for ARP spoofing attacks
• Should be secured and monitored
• Implement redundancy (HSRP, VRRP)

Related Topics

• Router
• Subnetting
• NAT
• ARP
• DHCP

---

Back to: 00-MOC-Cybersecurity-Roadmap