Your CCNA certification exam efforts have to include things like practicing with numerous password sorts and knowing easy methods to configure them on a Cisco router - but for CCNA exam success and to thrive in real-world networks, you also need to know the best way to examine a Cisco router configuration and identify the level of network security that is definitely already present. Immediately after all, most routers you function with currently have passwords set, and it is as much as you to establish if those passwords are finding the job carried out.
Let's start off with a telnet password. Telnet passwords are configured on the VTY lines, and no telnet access is enabled on a Cisco router by default. If you ever saw the following configuration, what would it mean?
line vty 0 4
privilege level 15
password baseball
login
That modest Cisco router configuration signifies 3 things - initially, Telnet access is enabled. Second, the password is baseball. Third, the "privilege level 15" command means that any user who attempts to Telnet towards the router and knows the password will automatically be placed into privileged exec mode. (If that command were not present, the user would be placed into user exec and after that prompted for the enable password just before becoming permitted into privileged exec.)
You could not need to give that amount of access to all incoming Telnet connections. In the event you walked into a client's router area and saw this configuration on a router, what would it mean to you?
username halas password 0 bears
username ewbank password 0 jets
username ed privilege 15 password 0 mcdaniel
line vty 0 four
login nearby
This configuration signifies 3 factors as well. Each and every user attempting to telnet in is going to be prompted for each a username and password. Each person user should enter the password that's been assigned to them. For example, the user "halas"would have to enter the password "bears" to successfully Telnet into this router. The command "login local" beneath the VTY lines means that this nearby database of usernames and passwords might be made use of for authentication.
Once again, by default, users who're Telnetting in will likely be placed into user exec mode by default. Only users with "privilege 15" inside the middle of their username / password definition will probably be placed into privileged exec promptly upon login.
Notice that zero in each of the username / password statements? I did not enter that when I configured these statements. This number indicates the degree of encryption the password is presently under; a zero is the lowest amount of encryption, indicating that the passwords are not encrypted at all. There's a single line near the top rated of a Cisco router configuration that tells you why.. which of these three is it?
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
Hassle-free adequate! The password encryption service is off by default. To turn it on. just run the command service password-encryption. Let's do so here and after that take a look at the configuration.
R1(config)#service password-encryption
username halas password 7 1415170A1E17
username ewbank password 7 070524585D
username ed privilege 15 password 7 082C4F4A08170C121E
Now that is what I call encryption! Note that the zero has altered to a "7" - that's the highest level of encryption on a Cisco router, and as you can see, it's quite helpful.
Understanding learn how to read a Cisco router configuration is a beneficial ability for both the CCNA certification exam and working with production networks. Maintain practicing, maintain studying, and you will have the coveted letters "CCNA" behind your name soon!
Chris Bryant, CCIE #12933, could be the owner of the Bryant Benefit, house of more than 100 cost-free certification exam tutorials, such as Cisco CCNA certification test prep articles. His exclusive Cisco CCNA study guide and Cisco CCNA coaching is also attainable!
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