14-30 User’s Reference Guide

Firewall tutorial

General Firewall Terms

Firewall: a component or set of components that restrict access between a protected network and the Internet, or between two networks.

Host: A workstation on the Network.

Packet: Unit of communication on the Internet.

Packet Filter: Packet filters allow or deny packets based on source or destination IP addresses, TCP or UDP ports, or the TCP ACK bit.

Port: A number that defines a particular type of service.

Filter Rule: A filter set is comprised of individual filter rules.

Filter Set: A grouping of individual filter rules.

Basic IP Packet Components

All IP packets contain the same basic “header” information, as follows:

Source IP Address

163.176.132.18

 

 

Destination IP Address

163.176.4.27

 

 

Source Port

2541

 

 

Destination Port

80

 

 

Protocol

TCP

 

 

ACK Bit

Yes

 

 

DATA

User Data

 

 

This header information is what the packet filter uses to make filtering decisions. It is important to note that a packet filter does not look into the IP datastream (the User Data from above) to make filtering decisions.

Basic Protocol Types

TCP: Transmission Control Protocol. TCP provides reliable packet delivery and has a retransmission mechanism (so packets are not lost). RFC 793 is the specification for TCP.

UDP: User Datagram Protocol. Unlike TCP, UDP does not guarantee reliable, sequenced packet delivery. If data does not reach its destination, UDP does not re transmit the data. RFC 768 is the specification for UDP.

And there are many more ports defined in the Assigned Addresses RFC.

Page 192
Image 192
Netopia R2121 manual Firewall tutorial General Firewall Terms, Basic IP Packet Components, Basic Protocol Types

R2121 specifications

The Netopia R2121 is a powerful and versatile router designed for both home and office environments, providing seamless connectivity and robust performance for various networking needs. This device offers a range of features and technologies that cater to the demands of modern users seeking reliable internet access, speed, and security.

One of the standout characteristics of the Netopia R2121 is its dual-band technology, which operates on both the 2.4 GHz and 5 GHz frequency bands. This capability allows users to enjoy faster speeds and less interference, as the 5 GHz band is typically less congested than the traditional 2.4 GHz band. With the ability to support multiple devices simultaneously, the R2121 ensures that users can stream videos, play online games, and conduct video conferences without experiencing lag or connectivity issues.

The router is equipped with advanced security features, including WPA3 encryption, which provides enhanced protection against unauthorized access and data breaches. The R2121 also supports a robust firewall system that guards against external threats, ensuring that the user's network remains secure. Additionally, the router includes parental controls, allowing users to manage and restrict internet access for specific devices or set time limits for usage, making it an excellent choice for families.

Another significant advantage of the Netopia R2121 is its extensive coverage area. With high-gain antennas and advanced beamforming technology, the router can deliver strong and stable Wi-Fi signals even in larger homes or office spaces. This technology focuses the Wi-Fi signal directly toward connected devices, minimizing dead zones and improving overall connectivity.

The R2121 also supports both IPv4 and IPv6, ensuring compatibility with current and future internet technologies. This forward-thinking design makes it a future-proof solution for users looking to invest in a reliable router.

In terms of setup and management, the Netopia R2121 features a user-friendly web interface that allows users to easily customize settings, monitor network performance, and manage connected devices. The inclusion of mobile app support further enhances the user experience, enabling remote monitoring and control of the network from anywhere.

Overall, the Netopia R2121 stands out as a robust and reliable router that combines advanced features, enhanced security, and excellent performance, making it an ideal choice for home and business users alike. With its focus on delivering seamless connectivity and comprehensive management options, the R2121 is well-suited for today's connected lifestyles.