CCNA Certification Exam Training: Passwords, Cisco Routers, And Network Security
by: Chris Bryant, CCIE #12933
CCNA certification is
important, and so is securing our network's Cisco routers! To reflect the importance of network security, your CCNA certification exam is likely going to contain a few questions about the various passwords
you can set on a Cisco router. Let's take a look at some of those passwords and when to apply them.
If the previous user has logged out of the router properly, you will see a prompt like this when
you sit down at the router console:
R1 con0 is now available
Press RETURN to get started.
To get into enable mode, by default all I have to do is type "enable".
See how the prompt changed? By default, I can now run all the show and debug commands
I want, not to mention entering global configuration mode and doing pretty much what I want. It just might be a good idea to password protect this mode! We do so with either the enable password command or
the enable secret command. Let's use the enable password command first.
R1(config)#enable password dolphins
Now when I log out and then go back to enable mode - or try to - I should be
prompted for the password "dolphins". Let's see what happens.
I was indeed prompted for a password. Cisco routers will not show asterisks
or any other character when you enter a password; in fact, the cursor doesn't even move.
The problem with the enable password command is that the password will show in the configuration in clear
text, making it easy for someone to look over your shoulder and note the password for future use, as shown below:
enable password dolphins
We could use the
"service password-encryption" command to encrypt the enable password, but that will also encrypt all the other passwords in the Cisco router config. That's not necessarily a bad thing! Here's the
effect of this command on the enable password we set earlier.
enable password 7 110D1609071A020217
Pretty effective encryption! However, if we want to have the enable password automatically
encrypted, we can use the enable secret command. I'll use that command here to set this password to "saints", and note that I'm not removing the previous enable password.
R1(config)#enable secret saints
After removing the "service password-encryption" command, we're left with two enable mode passwords, and they appear in the Cisco router config like this:
enable password dolphins
enable secret 5 $1$kJB6$fPuVebg7uMnoj5KV4GUKI/
If we have two enable passwords, which one should we use to log into the router? Let's try the first password,
When you're prompted for the password a second time, you know you got it wrong the first time! Let's try
When both the enable secret and enable password commands are in use on a Cisco router, the enable secret
password always takes precedence. "dolphins" didn't get us in, but "saints" did. That's valuable information for both the CCNA certification exam and real-world networks, because there's
no worse feeling than typing a password at a Cisco router prompt and then getting another password prompt!
This is just one way to perform basic Cisco router security with passwords. We'll take a
look at other methods in a future CCNA certification exam training tutorial!
This article was posted on February 14, 2007
About The Author
Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com).
For his FREE seven-part
course, "How To Pass The CCNA", visit the website and sign up today! Daily free CCNA, CCNP, Network+, Security+, and A+ certification questions, too!