14-8 User’s Reference Guide

Port numbers

A filter can also match a packet’s port number attributes, but only if the filter’s protocol type is set to TCP or UDP, since only those protocols use port numbers. The filter can be configured to match the following:

The source port number (the port on the sending host that originated the packet)

The destination port number (the port on the receiving host that the packet is destined for)

By matching on a port number, a filter can be applied to selected TCP or UDP services, such as Telnet, FTP, and World Wide Web. The tables below show a few common services and their associated port numbers..

Internet service

TCP port

Internet service

TCP port

 

 

 

 

 

 

 

 

FTP

20/21

Finger

79

 

 

 

 

Telnet

23

World Wide Web

80

 

 

 

 

SMTP (mail)

25

News

144

 

 

 

 

Gopher

70

rlogin

513

 

 

 

 

 

 

 

 

Internet service

UDP port

Internet service

UDP port

 

 

 

 

 

 

 

 

Who Is

43

AppleTalk Routing

202

 

 

Maintenance (at-rtmp)

 

 

 

 

 

World Wide Web

80

AppleTalk Name Binding

202

 

 

(at-nbp)

 

 

 

 

 

SNMP

161

AURP (AppleTalk)

387

 

 

 

 

TFTP

69

who

513

 

 

 

 

Port number comparisons

A filter can also use a comparison option to evaluate a packet’s source or destination port number. The comparison options are:

No Compare: No comparison of the port number specified in the filter with the packet’s port number.

Not Equal To: For the filter to match, the packet’s port number cannot equal the port number specified in the filter.

Less Than: For the filter to match, the packet’s port number must be less than the port number specified in the filter.

Less Than or Equal: For the filter to match, the packet’s port number must be less than or equal to the port number specified in the filter.

Equal: For the filter to match, the packet’s port number must equal the port number specified in the filter.

Greater Than: For the filter to match, the packet’s port number must be greater than the port number specified in the filter.

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Netopia R2121 manual Port numbers, Port number comparisons

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.