https://mrncciew.com/2012/12/27/understanding-dhcp/

Easy if you know how basic packets flow in network from one end to other. They want to know how it happens for the first time. DHCP DORA process in detais including packet contents.

DORA process packet contents? source & destination add. in each packets?

The second round was on site with one of the network support engineers. Purely technical and more in-depth (again proper Layer 1, 2 and 3 questions). Nothing tricky really, but you must know very well

The third round was with the technical support manager. Again similar questions + logical thinking check. e.g l was presented with the flan, without any details topology where all traffic was routed over the low-speed link. As there were no details of the link speed etc, you should ask, confirm and make next action plan on how to resolve the issue. Start troubleshooting from Layer 1 (check CRC errors) and so on.

The fourth round was on site again with three different tech manages. Checking personality, how you would react in the certain situation and again tech stuff. Tech stuff is fine as long as you know Layer 1, 2 and 3 very well

2nd round on webex, fully technical, pinging and troubleshooting, prepare vlans stp and layer 3, they want you to know all the basics thoroughly and deal with it. You won`t even know where you are going wrong,I missed completing the troubleshooting by 1 step and didn`t get selected. Maybe lacked technical expertise

Q-DHCP ? Working ? DORA - what types of messages are sent on each step ? (broadcast/unicast/multicast)

you need to know in and out about troubleshooting layers 1 - 4 to crack the interviews. Having CCNA / CCNP helps the process.

Cant reveal the questions. But you need to know the in and out of DHCP, STP, ARP, basic routing, port security and troubleshooting. Basics basics basics.... that is the only requirement.

Second interview was a technical interview, through Webex. Diagrams on networking. Pointed questions. Interviewer will explain points that are unknown or not answered and give a chance to complete if it rings a bell.

before progressing on to interviews with existing engineers which are mainly technical and involve some scenarios they ask you to troubleshoot.

The scenarios are relatively easy if you have an existing background in Networks, as you'll have a good idea of what questions to ask in order to narrow down the problem.

Technical questions mostly involve describing network protocols, how they work, and other fundamental concepts. There's little room for error, you'll be expected to more-or-less parrot an exact detailed dictionary definition for each.

Basic troubleshooting questions. They draw a basic topology and a user on one end is not able to ping. They dont give you any other details. You have to ask questions.

The interviewers are nice and friendly and are looking for the approach you take to troubleshoot issues. If you have strong fundamentals and can express yourself clearly you should be able to clear this interview.

DHCP troubleshooting scenario ( helper address)

1st was HR round, 2nd troubleshooting on cisco switches and the last on troubleshooting of router

Interview Questions

  • how VLANS work. troubleshooting scenario was given and questions were asked on that.Tip- prepare your CCNA properly.

The Interview covered Layer 2 and the other half covering layer 3 questions. Must know at least CCNA and understand fundamental networking concepts to get the job.

Interview Questions

  • Explain Layer 2 and Layer 3 functionality
  • Technical questions are troubleshooting questions surrounding topics such as ARP, ping,VLAN,subnetting,etc.

2 video calls with the support engineers. They expect you to know everything including the reason for failure, the commands, port numbers, ACL, routing tables and they expect you to start working on the first day given an offer.

Interview Questions

  • They provide you with hard topologies and would ask you how you would troubleshoot them.

Following the call, I completed a writing sample and two technical interviews. The writing sample was straightforward, and the technical interviews were what I expected.

My final set of interviews was at the Meraki office in SF. I hadthree interviews with managers, two included technical questions. I was initially also meeting two network support engineers for personality interviews, however the schedule didn't allow it.Show Less

Interview Questions

  • Two hosts are connected by a L2 switch. Host A mac:AAA IP:1111 Host B mac:BBB IP:2222. Explain in detail the process of a ping from host A to host B.
    2 Answers
  • Given a basic topology on a whiteboard, a client is experiencing an issue. Diagnose and suggest a solution.

(UK)Next was a face to face interview in London which consisted of rounds with staff & management staff with more technical questions as well as checking if you will fit into the culture. Such questions were detailed information regarding packets & frames, STP, DHCP & Wireless, VPNs & ARP as well as some troubleshooting. Most of CCNP Tshoot, Routing and Switching.
Next was a Skype interview with senior management which included troubleshooting scenarios & checking your interests and personality. The last stage was a interview in San Francisco where there was more culture based questions checking your interests and background and passion as well as a further troubleshooting scenario.
All in all a 4 step interview: Phone, Face to Face, Skype, San FranciscoShow Less

Interview Questions

  • Explain exactly how the STP election process works and what BPU's do in this process.

How to packets travel across a switched network?

What is the purpose of vlan tagging?

What is contained in a DHCP packets?

Each interview went through a networking scenario where something(s) was causing an issue with the network and you had to work through things to find and resolve it. Need to know: how ARP works, DHCP, basic packet contents, DNS, ACL, subnets, among others.

Don't be surprised if the interviewers are late. I don't think a single one of mine

started on time.

Eventually I was invited to interview at their HQ. There were 3 interviews there with the support managers, each similar but in a bit more detail than the Skype interviews with of course some standard "why do you want to work for us" questions as well. Meraki paid for flight/hotel for this process which was very nice.

The entire process was pretty straightforward and tough because they want Support Engineers that know the fundamentals extremely well and can function well under duress. You need a very strong understanding of network fundamentals (OSI, TCP/IP, VLANs, etc...) and be able to apply those concepts to real life troubleshooting scenarios (this is obvious, but needs to emphasized). Although you don't need to regurgitate IOS commands, you will need to be verbally troubleshoot, so I recommend doing a lot of labs.

1) Phone interview w/manager consisting of a few personality questions (Experience, why networking...) and then some basic technical questions - the OSI model stack, encapsulation, how frames are transmitted.

2) Written Assignment

A couple of days later:

3) Technical Video Conference interviews - I had 2 technical interviews over VC, each an hour long. These were pretty tough because the process is dynamic in the sense that the process is more interactive and the troubleshooting scenarios don't follow a specific prompt.

Note: It's about how you think under pressure, not how many concepts/commands you can regurgitate.

4) In-person interview w/senior managers - a mix between personality and technical questions. The Support Engineers and their managers are really smart, so they can sniff out BS quickly.

Describe what happens when a device pings another on the same network through a layer 2 device? Explain Spanning Tree Protocol? Describe process when you access a website from a home network (ie: three-way handshake), Describe a problem you have solved or worked through using Wireshark?

There were very technical questions such as, tell me about the dhcp process, what's the difference between a switch and a router. troubleshooting cases involving the use of ping command, traceroute, wireshark etc..

You must have a firm understanding of the concepts of Wireless, Networking and Security. You must be able to explain how packets travel across a network. Especially ARP , DHCP and STP etc.

Layer 2 must be very thorough. Don't be concerned with Cisco syntax. They do not use Cisco equipment. They have a separate line of Meraki switches, APs and Firewalls. All of which is primarily in GUI since Meraki is into Software-Cloud managed networking. There are demos of the product on Youtube

Unfortunately/fortunately, the only way to troubleshoot is through packet captures. This means that anyone with a Cisco background will lose the CLI skills part of the job. In my opinion, this role also may not have much value in the future since the only company that would hire for Meraki experience is Cisco and packet capture using Wireshark is NOT a highly sought after skill. Incidentally,

  1. How do packets travel across a network?

( Explain using an ICMP example, use all the protocols. that are involved. DHCP, ARP etc. Keep in mind the OSI model)

  1. What is the difference between STP and RSTP?

Technical Interview:

  1. If you were to take an RF Wireless survey, would you do it when there were people in the room or when the room was empty?

Always when people are in the room, humans are 60-70% water and that means more attenuation. This will be an efficient survey, only if people are in the room.

  1. What happens when you type www.google.com into your computer?

  2. What does the 's' in https signify?

SSL communication between host and server

4.(Scenario Based) A host is trying to connect to a computer across a VPN tunnel but unfortunately it cannot access the resource. What could be the problem,assuming that the VPN tunnel is setup correctly?

The correct answer is the hosts file on the computer has an incorrect mapping of the name to ip. You will know this when you ping the name of host and it resolves to a different ip.

  1. (Scenario Based) A firewall in a corporate environment was one day replaced with a Meraki firewall. Now clients are no longer able to access the web server, The configuration on the different firewalls are identical. What could be the problem?

The ARP cache on the modem still points to an old mapping of the Firewall. The MAC address had now changed, Therefore in order to rectify the problem, power off and power on the modem.

  1. What is gratuitous ARP?

  2. What are the different modes with IPSec? What is IKE Phase 1 and IKE Phase 2?

main mode and quick mode

  1. (Scenario-Based ), three switches are connected together in a triangle design, A, B and C, Who becomes the Root bridge? What is the default priority on Cisco switches? Can a switch have a priority of 0? When the speed of the links are changed, does the root port also change?

  2. What is the difference between PVST and PVST+?

  3. Name one channel in a 5 GHz band?

  4. Explain to me how DNS works?

Cultural interview:

  1. (Scenario-based) There is a set of core and distribution switches, there are three VLANs spanned across all switches, RSTP is functioning correctly, a user connected to VLAN 2 cannot access the internet, what could be the problem?

Ans: you must deduce that if everything is configured correctly and there are no physical issues with the network, the correct answer is that there is a rogue DHCP server in VLAN 2. You need to shutdown the port connected to the rogue DHCP server. First, find out the MAC address of the rogue DHCP server from the arp cache of the host computer. arp -a. Secondly, from the CAM address table of the switch, see which port is associated with the MAC address. Thirdly, block the port.Fourthly, ipconfig /release and ipconfig /renew on the host computer to get a legitimate IP address from the real DHCP server in VLAN 2.

Alternative solution would be to enable DHCP Snooping.

Interview Questions

  • Critically thinking, how would you stop layer 2 CAM table overflow attack?

    Describe and explain about STP and RSTP,

    Describe and explain about the differences between STP and RSTP.

    Describe and explain about HSRP, VRRP, or GLLP in detail.

    Describe and explain about DHCP and how it works in detail

    Describe and explain how TCP/IP establish connection between a server and a host in detail

    If you execute a ping command from your host computer to
    a server in a different subnet, describe in detail of what is going to happen.

    Describe and explain OSI layer model

    How does internet work? describe every process from layer 2 through layer 4 including a return traffic.

Explain the DHCP process, why is this host getting the wrong IP

Given a basic topology on a whiteboard, a client is

experiencing an issue. Diagnose and suggest a solution.

here are obviously a high number of questions that can be asked here, understanding of basic networking fundamentals is critical. DNS, ARP, TCP, VLANS, OSI Layers etc.

DHCP Client keeps on getting the wrong ip address...

TS:I would start by turning your dhcp server off and see if workstations still get this other subnet ip address. If so then you need to track down the second device serving dhcp. If not then I would look in the dhcp server and see if it is serving addresses from 2 different ip subnet pools.

Set the server back to DHCP config and have it renew its IP from the DHCP server. Go to a command prompt on the machine and run "ipconfig /all". Review the results - look for the DHCP server line. It will tell you where the machine is getting the address. If it is the machine itself, then see my post above. If it is your DHCP server, then check its settings and see if there may be an additional scope being delivered. If it is a different machine entirely, correct that machine, but you will at least know where the IP is initiated.

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