Networking Beginner

What is Firewall?

A network security system that monitors and controls incoming and outgoing traffic based on predetermined rules.

Firewalls act as gatekeepers between trusted internal networks and untrusted external networks. They filter traffic based on IP addresses, ports, protocols, and application data.

Types include packet filtering, stateful inspection, proxy, and next-generation firewalls (NGFW). Linux uses iptables or nftables. Common tools include UFW (Ubuntu) and firewalld (RHEL/CentOS).

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Related Terms

NAT (Network Address Translation)

A method of mapping private IP addresses to public IP addresses, allowing multiple devices to share a single public IP.

A logical division of an IP network into smaller segments to improve performance, security, and management.

A network routing technique where the same IP address is announced from multiple locations, directing users to the nearest server.

DNS over HTTPS (DoH)

A protocol that encrypts DNS queries by sending them over HTTPS, preventing eavesdropping and manipulation of DNS traffic.

VLAN (Virtual LAN)

A logical grouping of network devices that creates separate broadcast domains on the same physical network infrastructure.

A network communication method that sends data to multiple recipients simultaneously without duplicating packets for each recipient.

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