What is Named and Numbered ACL in Cisco Networking ?
In Cisco networking, Access Control Lists (ACLs) can be classified into two main types: named ACLs and numbered ACLs. These two types serve the same fundamental purpose of controlling network traffic, but they are configured and referenced differently.
Numbered ACLs:
* Numbered ACLs are identified by a simple numeric value, such as 1, 2, 3, etc.
* They are typically used in older Cisco IOS versions, particularly in standard ACLs.
* Numbered ACLs are less flexible because if you want to insert a new ACL between existing numbered ACLs, you would need to renumber them, which can be cumbersome.
* They are also less descriptive since the ACLs are referred to by their numbers rather than meaningful names.
* Numbered ACLs are still in use, but named ACLs are generally preferred for their flexibility and readability.
Example of a numbered standard ACL to permit traffic from a specific source IP address:
access-list 1 permit 192.168.1.1
Named ACLs:
* Named ACLs are identified by a user-defined name, making them more human-readable and easier to manage.
* They can be used for both standard and extended ACLs, offering greater flexibility.
* Named ACLs are more manageable because you can insert new ACLs without the need to renumber existing ones.
* They are generally recommended in modern Cisco networking configurations due to their advantages in terms of readability and maintenance.
Example of a named standard ACL to permit traffic from a specific source IP address:
ip access-list standard MY_ACL
permit 192.168.1.1
In the above example, "MY_ACL" is the user-defined name for the ACL.
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