Access Control List Commands 4

Default Setting

None

Command Mode

Extended ACL

Command Usage

•All new rules are appended to the end of the list.

•Address bitmasks are similar to a subnet mask, containing four integers from 0 to 255, each separated by a period. The binary mask uses 1 bits to indicate “match” and 0 bits to indicate “ignore.” The bitmask is bitwise ANDed with the specified source IP address, and then compared with the address for each IP packet entering the port(s) to which this ACL has been assigned.

•You can specify both Precedence and ToS in the same rule. However, if DSCP is used, then neither Precedence nor ToS can be specified.

•The control-code bitmask is a decimal number (representing an equivalent bit mask) that is applied to the control code. Enter a decimal number, where the equivalent binary bit “1” means to match a bit and “0” means to ignore a bit. The following bits may be specified:

-1 (fin) – Finish

-2 (syn) – Synchronize

-4 (rst) – Reset

-8 (psh) – Push

-16 (ack) – Acknowledgement

-32 (urg) – Urgent pointer

For example, use the code value and mask below to catch packets with the following flags set:

-SYN flag valid, use “control-code 2 2”

-Both SYN and ACK valid, use “control-code 18 18”

-SYN valid and ACK invalid, use “control-code 2 18”

Example

This example accepts any incoming packets if the source address is within subnet 10.7.1.x. For example, if the rule is matched; i.e., the rule (10.7.1.0 & 255.255.255.0) equals the masked address (10.7.1.2 & 255.255.255.0), the packet passes through.

Console(config-ext-acl)#permit 10.7.1.1 255.255.255.0 any

Console(config-ext-acl)#

This allows TCP packets from class C addresses 192.168.1.0 to any destination address when set for destination TCP port 80 (i.e., HTTP).

Console(config-ext-acl)#permit 192.168.1.0 255.255.255.0 any destination-port 80

Console(config-ext-acl)#

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LevelOne GSW-2692 manual Extended ACL
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GSW-2692 specifications

The LevelOne GSW-2692 is an advanced Layer 2 Gigabit Ethernet switch that is designed to cater to the networking needs of both small and medium-sized enterprises. Highly regarded for its reliability and performance, the GSW-2692 offers 24 Gigabit Ethernet ports, enabling seamless and high-speed data transfers across connected devices. With its robust design and versatile capabilities, this switch has earned its place as an essential component in modern IT infrastructure.

One of the standout features of the GSW-2692 is its extensive support for advanced networking technologies. The switch includes support for IEEE 802.1Q VLAN tagging, which allows users to create separate virtual networks for improved traffic management and enhanced security. By segregating network traffic, businesses can optimize bandwidth usage and reduce congestion, contributing to overall increased network performance.

Additionally, the GSW-2692 supports Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol (RSTP), ensuring loop-free network topology. This capability is crucial in larger networking environments where multiple switches are interconnected, as it prevents broadcast storms and enhances network resilience. The switch also includes features such as port mirroring, which provides administrators with the capability to monitor network traffic in real-time for troubleshooting and analysis.

Power over Ethernet (PoE) support is another significant advantage of the GSW-2692. With PoE functionality, it enables the switch to deliver electrical power along with data to connected devices such as IP cameras, VoIP phones, and wireless access points, eliminating the need for additional power sources and simplifying installations.

In terms of physical characteristics, the LevelOne GSW-2692 is designed for efficient heat dissipation and features a fanless design, which ensures silent operation. Its desktop or rack-mountable options make it flexible for various installation environments. The switch also features a web-based management interface, which simplifies the configuration and monitoring processes, allowing for intuitive management of network settings.

Overall, the LevelOne GSW-2692 stands out as a feature-rich, reliable, and high-performance networking solution that meets the demands of modern enterprises. Its combination of advanced technologies, scalability, and ease of use makes it an excellent choice for businesses looking to enhance their network infrastructure.
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