Questions asked for a CCNA level Job interview

SysnetNotes

I moved to networking field from another industry.I know there are lot of experienced people in this forum.What are the common questions that can be expected in a CCNA level technical interview round.Also please share the difficult questions you experienced in real interviews.

Hope this thread will help a lot of people like me

theodoxa

1. Explain the OSI Model
2. An interface is "Up/Down" [or some other state], how would you troubleshoot it? What might the problem be?
3. How would you determine if there is a problem with the network?
4. What WAN Protocols/Types have you worked with?
5. [I seem to remember being asked about Routing Protocols I had worked with also, but I don't remember the wording of the question.]
6. What Cisco equipment have you worked with?

I'm sure others have run into other questions. Another question I received in a Non-CCNA interview, but could be relevant to a CCNA position also:

1. A user has complained that they are not able to access [INSERT A SPECIFIC SERVER, THE INTERNET, OR SOMETHING ELSE], how would you determine the problem and fix it?

Alot of questions I've run into are trying to see how you would troubleshoot network issues.

NetworkVeteran

SysnetNotes wrote: »

I moved to networking field from another industry.I know there are lot of experienced people in this forum.What are the common questions that can be expected in a CCNA level technical interview round.Also please share the difficult questions you experienced in real interviews.

Hope this thread will help a lot of people like me

Since employees have some confidence but not certainty you know the CCNA topics, anything that was covered by the CCNA study materials and/or exam is fair game. I would add to that anything you claimed on your resume. As theodoxa says, seeing how you would handle new / unexpected situations is especially important at the entry-level, since it can be expected that a fair number of situations will be new and unexpected and require thinking on your feet.

Difficult questions? Explain whatt happens when you turn on your PC and ping Google!

Dieg0M

Other questions I've heard asked to some members getting interviewed:
What is the difference between a link state and a path vector protocol?
What is TCP/IP?
What kind of protocol is EIGRP and explain why?
What's a window in networking terms?
How do you detect and fix network congestion?
What is a Designated Router?

And some others.

Zartanasaurus

Go up to the whiteboard and diagram your network for me.

Cat5

I had a brain-freeze recently when I was asked "what does OSPF stand for?" I didn't get the job - I hope my mental lapse didn't cause it.

itgl72

I was going to start a thread like this. Great job, lets keep it going.

SysnetNotes

Below 3 questions was asked to one of my friend in a interview

what is meant by UDLD ?
Is that possible to use RIP in a network having more than 15 routers ?
What is the difference between OSPF v2 and V3 ?

olaHalo

Zartanasaurus wrote: »

Go up to the whiteboard and diagram your network for me.

This is my favorite.
When I was hired at my most recent job I asked two coworkers to do this.
Their diagrams were completely different.

Somnipotent

Subnetting has always reared it's ugly head. You can't simply memorize answers so it makes a very solid baseline for what questions to ask. Whiteboard has been and always will be my favorite method of interviewing. When one day I become the hiring manager, I'm definitely setting up a configuration lab.

networker050184

I always ask them to walk me through arp and how addresses change as a packet travels through a network. You'd be amazed by how many people with their CCNA/CCNP do not know the simple building blocks of networking. You may know how to type 'router ospf 1' all day long but if you can't figure out why something can't communicate at the lowest level you're useless.

smcclenaghan

Cat5 wrote: »

I had a brain-freeze recently when I was asked "what does OSPF stand for?" I didn't get the job - I hope my mental lapse didn't cause it.

Seems like a silly interview question. A better one might have been to ask if you're allowed to disable automatic summarization for it, or anything that shows you use it rather than just being able to recite an acronym. Just my $0.02.

smcclenaghan

SysnetNotes wrote: »

Below 3 questions was asked to one of my friend in a interview

what is meant by UDLD ?
Is that possible to use RIP in a network having more than 15 routers ?
What is the difference between OSPF v2 and V3 ?

1. I never heard of UDLD until I just googled it.
2. My answer would be as long as they weren't all in a row (and subnet 1 didn't need to traverse 2-15 to reach 16).
3. Two weeks ago while finishing my studying for ICND2 I just learned about OSPFv3 being required for IPV6.

Do I get the job?

Dieg0M

I can see interviewers using this thread against us.

TurK-FX

I just had an interview last week, question was differences between tcp and udp

homemade88

1). What's the purpose of the Spanning Tree Protocol.
2). Explain NAT
3). What's the Differences between a switch and a router.
4). What's the purpose a VLANs
5). What's the purpose of using subnetting in a network

Keep in mind however, that these questions weren't ask for an IP/Network Engineer position, It was for the position of Commercial Technical Engineer/PBX Technician (which I got by the way, yay me) so I left out all the Phone related questions.

SysnetNotes

homemade88 wrote: »

1). What's the purpose of the Spanning Tree Protocol.
2). Explain NAT
3). What's the Differences between a switch and a router.
4). What's the purpose a VLANs
5). What's the purpose of using subnetting in a network

Keep in mind however, that these questions weren't ask for an IP/Network Engineer position, It was for the position of Commercial Technical Engineer/PBX Technician (which I got by the way, yay me) so I left out all the Phone related questions.

What's the purpose of the Spanning Tree Protocol ?
STP helps to avoid loops in the switching network


What's the purpose a VLANs ?
VLAN's separate a Layer-2 switch into multiple broadcast domains. Each VLAN is its own individual broadcast domain.Individual ports or groups of ports can be assigned to a specific VLAN. Only ports belonging to the same VLAN can freely communicate to each other.Broadcasts from one VLAN will never be sent out ports belonging to another VLAN


What's the purpose of using subnetting in a network ?
Reduce the size of the routing tables.
Reduce network traffic.
Broadcast traffic can be isolated within a single logical network.
Provide a way to secure network traffic by isolating it from the rest of the network.

WilyOne

smcclenaghan wrote: »

1. I never heard of UDLD until I just googled it.

Same here. It's certainly not covered in any of the CCNA material, but now filed in my memory banks.

Hondabuff

UDLD is only used on your fiber ports. So when a fiber run has a broken line it will shut down the whole link. Since Multimode fiber has a TX and an RX side its easy to break one side and the other side still works. Like when a engineer makes a zip tie too tight in a IDF

NetworkVeteran

OP wrote:

Is that possible to use RIP in a network having more than 15 routers ?

smcclenaghan wrote: »

2. My answer would be as long as they weren't all in a row (and subnet 1 didn't need to traverse 2-15 to reach 16).

I'd answer "Yes!" as well, however entirely without any qualifications or preconditions.

("Is it possible?" not "Would all networks be reachable?")

(I also agree with your point, that it's entirely possible with a good design, summarization, and/or offset lists to create a network design with RIP that scales to 100s or 1000s of routers. Now, care must be taken to consider such a network not only when it's healthy but also when links go down, so as not to have a fragile/easily-broken network.)

Cyanic

networker050184 wrote: »

I always ask them to walk me through arp and how addresses change as a packet travels through a network. You'd be amazed by how many people with their CCNA/CCNP do not know the simple building blocks of networking. You may know how to type 'router ospf 1' all day long but if you can't figure out why something can't communicate at the lowest level you're useless.

Agreed, and since we mess around with applications too, I always ask them to explain TCP session creation, three way handshake. If they can correctly answer that, then I throw the trick question of explain how a TCP session is torn down. Yes I'm cruel.

Zartanasaurus

Cyanic wrote: »

Agreed, and since we mess around with applications too, I always ask them to explain TCP session creation, three way handshake. If they can correctly answer that, then I throw the trick question of explain how a TCP session is torn down. Yes I'm cruel.

How is that a trick question? I guess you could want to hear about TCP half-close, but that's not really a trick.

hellolin

That is not a trick question, everyone knows the TCP three way handshake, but few remembers the four way handshake happens when the session ends!

Magic Johnson

Zartanasaurus wrote: »

Go up to the whiteboard and diagram your network for me.

When you say 'your network' what network are you referring to?

New2Network

I'm new here just got my CCNA & it's certainly helping me . This is the best thread I've seen on the subject. I know it died but I hope we can keep it going

bharvey92

networker050184 wrote: »

I always ask them to walk me through arp and how addresses change as a packet travels through a network. You'd be amazed by how many people with their CCNA/CCNP do not know the simple building blocks of networking. You may know how to type 'router ospf 1' all day long but if you can't figure out why something can't communicate at the lowest level you're useless.

I had this in an interview, I've also had a question regarding STP. The topology was a three Layer 2 Switch layout and I had to explain what Switch would become root-bridge and the root-ports, designated-ports and blocked.

tecnodog7

This is HEAVEN for a person like me who will be going into the market soon.
Also i'm so happy I can seem to answer most of them.
Keep on going guys.

Pupil

These aren't things I've been asked, but what I would expect to come up in an interview

basic technical questions:

- what is ICMP? (no, it's not just ping)
- what is a gateway of last resort?
- what is X port or Y protocol?
- what is routing on a stick?
- what is port aggregation?
- explain what GRE is and how it is used
- what are the advantages of using NetFlow, SNMP, etc. ?
- why are first-hop redundancy protocols used?
- why might you implement dynamic routing on links between layer 3 switches instead of STP?

troubleshooting scenario questions:

- you've configured a serial link between two routers, assigned IP addresses, and brought the interfaces up using no shutdown. One of the routers is showing status/protocol down when you run show ip int br, what could be the reason?
- you've configured OSPF on two routers, but they fail to form a neighbor adjacency. What are some possible reasons why?
- you've configured PAT, but hosts are unable to surf the web. How would you troubleshoot this scenario?
- you've configured EtherChannel between two switches, but the port-channel interface is still down. What could be the reason?

OfWolfAndMan

I know not all of these are CCNA level questions, but it's good to know I guess.

-What is the different between a root port and designated port?
-How do you configure a switch to be the root bridge?
-What is the difference between an access port and a trunk port?
-How often are BPDUs sent out in an STP topology?
-Describe to me how a layer 2 loop could occur (I'd advise saying more than "Don't disable STP")
-How would you configure HSRP?
-What is the purpose of route maps?
-What is an ether channel?
-(Not really a R&S question, but possible if dealing with load balancers): Describe to me some methods of load balancing.