Cisco CCNA (640-553) Security Training
Using the “access-list dynamic-extend” command
By Charles Ross CCNA - CCNP #CSCO10444244
In today’s article, I’m going to quickly inform you about the Cisco IOS Global configuration command named “access-list dynamic-extend”.
Network administrators (like you) use the “access-list dynamic-extend” to allow the absolute timer of the dynamic access control list (ACL) to be extended an additional six minutes.
In other words, after you’ve enabled the lock-and-key function by using the access-enable command and attempt to create a Telnet session to the router to re-authenticate yourself; you can use “access-list dynamic-extend” command to extend the absolute timer of the dynamic ACL by six minutes.
Note: If you need to use the command, make sure you implement it before the ACL expires.
Below is the command’s syntax:
access-list dynamic-extend
As you can see, the command is really easy to use; it doesn’t have any keywords or arguments.
And, here’s an example of the command being typed on a router.
Router>enable
Router#configure terminal
Router(config)#access-list dynamic-extend
Router(config)#exit
Router#copy run start
In the example above, the router is being configured with the command.
And, like with mostly all Cisco IOS commands; you can use the word “no” in front of the command to remove (disable) the configured command; like you see below:
Router(config)#no access-list dynamic-extend
By the way, if you decide to use the command, make sure your router(s) is running Cisco IOS 12.1(5)T or higher.
I hope this article was very informative and helped you quickly understand the usage of the access-list dynamic-extend command. If you need to learn more; I suggest you visit my website, (www.ittechtips.com) were you’ll find the latest information regarding the Cisco CCNA (640-553) Security exam techniques.
To your success,
Charles Ross
CCNA- CCNP #CSCO10444244