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Your CCNA certification exam is likely going to contain questions about Telnet, an application-level protocol that allows remote communication between two networking devices. With Telnet use being as common as it is, you had better know the details of how to configure it in order to pass your CCNA exam and to work in real-world networks.

The basic concept is pretty simple - we want to configure R1, but we're at R2. If we telnet successfully to R1, we will be able to configure R1 if we've been given the proper permission levels. In this CCNA case study, R2 has an IP address of 172.12.123.2 and R1 an address of 172.12.123.1. Let's try to telnet from R2 to R1.

R2#telnet 172.12.123.1

Trying 172.12.123.1 ... open

Password required, but none set

[Connection to 172.12.123.1 closed by foreign host]

This seems like a problem, but it's a problem we're happy to have. A Cisco router will not let any user telnet to it by default. That's a good thing, because we don't want just anyone connecting to our router! The "password required" message means that no password has been set on the VTY lines on R1. Let's do so now.

R1(config)#line vty 0 4

R1(config-line)#password baseball

A password of "baseball" has been set on the VTY lines, so we shouldn't have any trouble using Telnet to get from R2 to R1. Let's try that now.

R2#telnet 172.12.123.1

Trying 172.12.123.1 ... open

User access Verification

Password:

R1>

We're in, and placed into user exec mode. Let's say we want to configure a new IP address on the ethernet interface on R1. We'll now go into privileged exec mode....

R1>enable

% No password set

R1>

.. or maybe we won't! The default behavior of Telnet on a Cisco router is to place the incoming user into user exec mode, and require an enable password to allow that user into privileged exec mode! right now, we can't configure anything on this router and even the show commands we would use are limited at best.

If we wanted to allow all telnetting users to be put into privileged exec mode immediately without being prompted for an enable password, the command privilege level 15 placed on the VTY lines will accomplish this.

R1(config)#line vty 0 4

R1(config-line)#privilege level 15

From R2, we'll telnet into R1 again.

R2#telnet 172.12.123.1

Trying 172.12.123.1 ... open

User access Verification

Password:

R1#

We were able to telnet in from R2 with the original password of "baseball", and even better, we were placed into privileged exec mode immediately!

You may or may not want to do this in real-world networks, though. If you want to assign privilege levels on an individual user basis, configure usernames and passwords and use the privilege 15 command in the actual username/password command itself to give this privilege levels to some users but not all.

R1(config)#username heidi password klum

R1(config)#username tim privilege 15 password gunn

Both users can telnet into the router, but the first user will be placed into user exec and challenged for the enable password to enter privileged exec mode. If there is no enable password, the user literally cannot get into privileged exec. The second user will be placed into privileged exec immediately after successfully authenticating.

Passwords on a Cisco router or switch are vitally important, and you're not tied down to granting "all-or-nothing" access. Knowing the details like the ones shown here help you tie down network security while allowing people to do their jobs - and it doesn't hurt to know this stuff for the CCNA exam, either!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com).

posted by 45193  # 4:55 PM 0 comments

golf hook is one of the major difficulties and setbacks to an amateur golfer. There are a number of golf websites and golf training institutes that provide lessons to eradicate the hook in a golfers swing shot. However not mere lessons could contribute in the improvement of play and avoiding the golf hook as golf in itself is a hard to master game requiring immense concentration, perfect balance and the perfect application of physics that could be achieved only when there is a lot of practice. Even pros and champions spend a lot of time practicing their shots in every possible venue from their backyard to practice golf sessions to achieve perfections especially with their swing shots.

To begin with it is important to understand what a golf hook is even before looking out for lessons to avoid it. When swinging in golf games, if the axis of the golf ball gets tilted to the left resulting in a counter clockwise spin of the golf ball and the golf ball ending up to the far left of the target line unintentionally, it is called a hook. The target line is the line that would connect the current position where the shot is taken to the hole which is actually the line that the golf ball is supposed to follow to be put into the hole. Needless to say that golf hook is an embarrassment to the golfer and makes putting all the more difficult with all the messed up trajectories.

A golf hook happens when the golf ball is not hit in a squarer fashion during the swing. Hitting squarer means that the head of the golf club should be at right angles to the golf ball during the impact in a golf swing; that lofts the golf ball up in a parabola with the target line as its axis. In other words, the face of the golf head should not be tilted during the impact and the club should end up perfectly at the target point. Conventionally this definition is based on a right handed game and if the golfer is a left hander (and he plays left handed which is not often the case), the directions should be reversed. To many amateur golfers this is a tough deal and golf lessons in websites and the golf lessons provided by trainers to avoid golf hooks are centered on making the swing squarer.

Most golf lessons that are targeted towards reducing hooks concentrate on something called strong grip. According to these golf swing lessons, there should be a delicate balance between too much grip and too less grip. When having three or more knuckles on the club during the swing, the club tends to close inwards during the impact and hence the axis of the golf ball gets changed resulting in a hook. Most of these lessons recommend a two knuckle firm grip to ensure that just the right amount of grip and a far squarer shot is played in the swing.

You can improve your golf game with proven golf swing tips that can help lower your golf score by visiting http://www.onlinegolfer.com, a popular golfing website that provides tips, advice and resources, golf driving tips and the best selling golf ebooks that will improve your golf game.

posted by 45193  # 1:36 AM 0 comments