Cisco Ccna (640-553) Security Training: Using The Aaa Authorization Reverse-access Command

In today’s article, I’m going to quickly inform you about the Cisco IOS global configuration mode command named “aaa authorization reverse-access”.

So on that note let’s begin, CCNA’s (like you) use the “aaa authorization reverse-access” command to tell (configure) a network access server (NAS) router to request authorization information from either a TACACS+ or RADIUS security server before allowing a user to establish a reverse Telnet session.

In other words, an internal network administrator may sometimes need to perform a reverse Telnet session, so in order to gain control of a modem that is connected to a network access server (NAS) router; so he or she can make a call. If the network access server (NAS) router is configured with the “aaa authorization reverse-access” command, the router will check with either a TACACS+ or RADIUS security server first, to see if it’s o.k. for the network administrator to establish a reverse Telnet session to gain control of the modem to make the call.

Note: If a network access server (NAS) router is not configured with the command, it will automatically authorize all reverse Telnet sessions by default.

Below is the command’s syntax:

aaa authorization reverse-access {group radius | group tacacs+}

As you can see, the command is fairly simple to use; and it only has two keywords “group radius” or “group tacacs+”.

group radius – This keyword is used to specify that the network access server router will request authorization from a RADIUS security server before allowing a user to establish a reverse Telnet session.

group tacacs+ -- This keyword is used to specify that the network access server router will request authorization from a TACACS+ security server before allowing a user to establish a reverse Telnet session.

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 aaa authorization reverse-access {group radius | group tacacs+}

By the way, if you decide to use the command, make sure your router(s) is running Cisco IOS 12.0(5)T or higher.

I hope this article was very informative and helped you quickly understand the usage of the aaa authorization reverse-access command. If you need to learn more; I suggest you visit my website, were you’ll find the latest information regarding the Cisco CCNA (640-553) Security exam techniques.

To your success,

By: Charles E Ross

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Charles Ross, CCNP #CSCO10444244 is the owner of Ittechtips.com; where you'll find free comprehensive information and videos on how to pass the CCNA (640-553) security exam. Sign-Up for "100 Free Videos" and, also learn more about the new "Cisco CCNA (640-553) Video Accelerated Training Course" at his website. www.ccnaittechtips.com