Friday, June 29, 2012

CCNA Example Questions Part 1


And now for something different.  Below are 5 random questions that are typically found in Cisco CCNA (Cisco Certified Network Associate) accreditation exams.  Answers at the bottom of the post.



1. What is port 53 used for?

A.) FTP data
B.) FTP program
C.) Telnet
D.) DNS
E.) TFTP

2. What layer of the OSI Reference Model sends and receives bits and specifies the electrical, mechanical, procedural and functional requirements for maintaining a physical link between end systems?

A.) Session
B.) Transport
C.) Network
D.) Data Link
E.) Physical

3. Each port on a switch is a separate broadcast domain?

A.) True
B.) False

4, What would happen if you put the following ACL on an interface?

access-list 1 deny 172.168.0.1
access-list 1 deny 192.5.2.1

A.) All traffic from 172.168.0.1 and 192.5.2.1 would be denied
B.) All traffic would be denied
C.) Nothing
D.) These are not Cisco IOS ACL commands

5. What is the length of the MAC address in bits?

A.) 32 bits
B.) 48 bits
C.) 12 bits
D.) 80 bits

1 minutes explanation of IP address and subnet mask




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1. Answer D  DNS uses port 53
2. Answer E  Physical layer
3. Answer B  Switches form individual collision domains but a single broadcast domain
4. Answer B  An access list has an explicit deny all statement at the bottom, to prevent this the general catch all statement access-list 1 permit any  is used at the end of the list.
5. Answer B A MAC address is 48 bits represented as 12 Hexadecimal characters.

How did you go? More questions will be published at random :-) 



Sunday, June 10, 2012

The first computer bug

An extract of a letter by Grace hopper detailing the first ever computer bug

In the summer of 1945 we where building Mark II; we had to build it in an awful rush - it was wartime - out of components we could get our hands on.  We where working in a World War 1 temporary building.  It was a hot summer and no air conditioning, so all the windows where open.  Mark II stopped, and we where trying to get her going. We finally found the relay that had failed.  Inside the relay - and these where large relays - was a moth that had been beaten to death by the relay.  We got a pair of tweezers, very carefully took out the moth, put it in the logbook and put scotch tape over it. 

Now the commander had a habit of coming into the room and saying "Are you making any numbers?" We had to have an excuse when we weren't making any numbers, we told him that we where debugging the computer.  This is where it started.







Full story and pictures here.