Why do you use the Access Control List ACLs in the router?
What Is an Access Control ListAn access control list (ACL) contains rules that grant or deny access to certain digital environments. There are two types of ACLs: Show
Originally, ACLs were the only way to achieve firewall protection. Today, there are many types of firewalls and alternatives to ACLs. However, organizations continue to use ACLs in conjunction with technologies like virtual private networks (VPNs) that specify which traffic should be encrypted and transferred through a VPN tunnel. Reasons to use an ACL:
Understanding Access Control ListsAccess Control Lists (ACLs) are a collection of permit and deny conditions, called rules, that provide security by blocking unauthorized users and allowing authorized users to access specific resources. ACLs can also provide traffic flow control, restrict contents of routing updates, and decide which types of traffic are forwarded or blocked. Normally ACLs reside in a firewall router or in a router connecting two internal networks. You can set up ACLs to control traffic at Layer 2, Layer 3, or Layer 4. MAC ACLs operate on Layer 2. IP ACLs operate on Layers 3 and 4. FeaturesACL support features include Flow-based Mirroring and ACL Logging.
Using ACLs to mirror traffic is called flow-based mirroring because the traffic flow is defined by the ACL classification rules. This is in contrast to port mirroring, where all traffic encountered on a specific interface is replicated on another interface. LimitationsThe following limitations apply to ACLs. These limitations are platform dependent.
MAC ACLsMAC ACLs are Layer 2 ACLs. You can configure the rules to inspect the following fields of a packet (limited by platform):
L2 ACLs can apply to one or more interfaces. Multiple access lists can be applied to a single interface - sequence number determines the order of execution. You can assign packets to queues using the assign queue option. IP ACLsIP ACLs classify for Layers 3 and 4. Each ACL is a set of up to ten rules applied to inbound traffic. Each rule specifies whether the contents of a given field should be used to permit or deny access to the network, and may apply to one or more of the following fields within a packet:
1. Create a MAC ACL by specifying a name. 2. Create an IP ACL by specifying a number. 3. Add new rules to the ACL. 4. Configure the match criteria for the rules. 5. Apply the ACL to one or more interfaces. Setting Up an IP ACL via CLIThe script in this section shows you how to set up an IP ACL with two rules, one applicable to TCP traffic and one to UDP traffic. The content of the two rules is the same. TCP and UDP packets will only be accepted by the Sun Netra CP3240 switch if the source and destination stations have IP addresses that fall within the defined sets. FIGURE 22-1 IP ACL Example Network Diagram Example 1: Create ACL 179 and Define an ACL RuleAfter the mask has been applied, it permits packets carrying TCP traffic that matches the specified Source IP address, and sends these packets to the specified Destination IP address.
Example 2: Define the Second Rule for ACL 179Define the rule to set similar conditions for UDP traffic as for TCP traffic.
Example 3: Apply the rule to Inbound Traffic on Port 1/0/2Only traffic matching the criteria will be accepted.
Setting Up a MAC ACL via CLIThe following are examples of the commands used for the MAC ACLs feature. Example 1: Set up a MAC Access List
Example 2: Specify MAC ACL Attributes
Example 3: Configure MAC Access Group
Example 4: Set up an ACL with Permit Action
Example 5: Show MAC Access Lists
Setting Up ACLs via Web InterfaceThe following web pages are used in the ACL feature. FIGURE 22-2 MAC ACL Configuration Page - Create New MAC ACL FIGURE 22-3 MAC ACL Configuration Page FIGURE 22-4 MAC ACL Summary FIGURE 22-5 MAC ACL Rule Configuration - Create New Rule FIGURE 22-6 MAC ACL Rule Configuration Page - Add Destination MAC and MAC Mask FIGURE 22-7 MAC ACL Rule Configuration Page - View the Current Settings FIGURE 22-8 MAC ACL Rule Configuration Page - Add Destination MAC and MAC Mask FIGURE 22-9 MAC ACL Rule Configuration Page - Add Destination MAC and MAC Mask FIGURE 22-10 ACL Interface Configuration FIGURE 22-11 IP ACL Configuration Page - Create a New IP ACL FIGURE 22-12 IP ACL Configuration Page - Create a Rule and Assign an ID FIGURE 22-13 IP ACL Configure IP ACL Rule Properties FIGURE 22-14 IP ACL Rule Configuration Page - Rule with Protocol and Source IP Configuration FIGURE 22-15 Attach IP ACL to an Interface FIGURE 22-16 IP ACL Summary © 2007 Diversified Technology, Inc. All Rights Reserved. © 2009 Sun Microsystems, Inc. All rights reserved. Access Control ListAccess Control List (ACL) refers to a specific set of rules used for filtering network traffic, especially in computer security settings. ACLs also allow specific system objects such as directories or file access to authorized users and denies access to unauthorized users. ACLs are mainly found in network devices with packet filtering capabilities including routers and switches. Access-Lists (ACL)
Access-list (ACL) is a set of rules defined for controlling network traffic and reducing network attacks. ACLs are used to filter traffic based on the set of rules defined for the incoming or outgoing of the network. ACL features –
Once the access-list is built, then it should be applied to inbound or outbound of the interface:
Types of ACL –
Also, there are two categories of access-list:
Rules for ACL –
Advantages of ACL –
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