Solved CCENT 100-105 test prep

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Hello ITPro TV instructors! So I have been through the entire CCENT course ICND1 v2 and v3 class through ITPro (great time to get started right when they retire an exam I know...) and finally scheduled my exam for later this month. I've been through all 300 practice test questions provided through the ITPro site and plan to hit them multiple more times.. I've been trying to stay disciplined and not venture into CCNA related material and just prep for the task at hand, CCENT.

I've been reviewing other online resources just as a sanity check and have been somewhat alarmed at some of the content I've come across that I didn't see in the ITPro course or practice exams.. For example,

Found a question related to the multicast address of an IPv6 router on your local subnet.. Forget how the question was worded exactly, then they gave various answers A-E:
A. FF02::2
B. FF01::1
C. FF02::A
etc....

I went back and reviewed the IPv6 ITPro course in CCENT 100-105 and my notes. It looks like you touched on the network prefix for multicast addresses in IPv6 (FF00::/8), but I don't recall ever hearing anything about something as specific above. Any idea if the CCENT 100-105 exam will expect us to know information like this? Is there more material you would recommend I review on IPv6 to be better prepared?

Another question I came across was related to IP helper in the DHCP config. Again, I went through the class segment on DHCP as well as my notes, and it doesn't appear like IP helper was covered.... Again wondering if this is something CCENT will expect us to be familiar with...?

Another question was related to Variable Length Subnet Mask or VLSM. Anothjer term I don't think I had heard at all through the course.. I am familiar with how to subnet at this point and can handle questions like "what is the network ID or broadcast address for the network containing the IP address 192.168.99.4/26", but some of these VSLM questions I've run across have just blown my mind. Any idea if VSLM shows up on CCENT or was the site I found this on turning me over to CCNA or above questions?

@Adam-Tyler said in CCENT 100-105 test prep:

Hello ITPro TV instructors! So I have been through the entire CCENT course ICND1 v2 and v3 class through ITPro (great time to get started right when they retire an exam I know...) and finally scheduled my exam for later this month. I've been through all 300 practice test questions provided through the ITPro site and plan to hit them multiple more times.. I've been trying to stay disciplined and not venture into CCNA related material and just prep for the task at hand, CCENT.

I've been reviewing other online resources just as a sanity check and have been somewhat alarmed at some of the content I've come across that I didn't see in the ITPro course or practice exams.. For example,

Found a question related to the multicast address of an IPv6 router on your local subnet.. Forget how the question was worded exactly, then they gave various answers A-E:
A. FF02::2
B. FF01::1
C. FF02::A
etc....

I went back and reviewed the IPv6 ITPro course in CCENT 100-105 and my notes. It looks like you touched on the network prefix for multicast addresses in IPv6 (FF00::/8), but I don't recall ever hearing anything about something as specific above. Any idea if the CCENT 100-105 exam will expect us to know information like this? Is there more material you would recommend I review on IPv6 to be better prepared?

The answers you provided don't give enough of answers to provide a proper answer. Is this about identifying a multicast address for IPv6 generically? Is this trying to see if you know which isn't an IPv6 multicast address? I'm not sure without the context of the question.

Another question I came across was related to IP helper in the DHCP config. Again, I went through the class segment on DHCP as well as my notes, and it doesn't appear like IP helper was covered.... Again wondering if this is something CCENT will expect us to be familiar with...?

We build the show based on the official exam objectives. It depends on what you need to know about the IP helper address according to question? is it where is it used? which interface on a router? or which of the following to you need to allow this computer to receive dhcp from 172.16.100.134/22? so we need more information if you're looking for something specific.

Another question was related to Variable Length Subnet Mask or VLSM. Anothjer term I don't think I had heard at all through the course.. I am familiar with how to subnet at this point and can handle questions like "what is the network ID or broadcast address for the network containing the IP address 192.168.99.4/26", but some of these VSLM questions I've run across have just blown my mind. Any idea if VSLM shows up on CCENT or was the site I found this on turning me over to CCNA or above questions?
As far as I know, you'll run into the VLSM concepts more the CCNA exam rather than the CCENT exam. The questions you're coming across for the CCENT about VLSM is probably not on the exam if we didn't cover it there. You will need to understand this concept very well for the CCNA R&R exam though.

I would suggest that to ensure that you studying for the exam you can go to cisco's website and get the exam objectives for both exams from there and download them. This way you'll know if questions you're seeing are on track or not.

My suggestion is to be careful about these sites that offer exam questions. Don't get me wrong, you may find some of them on the exam but they don't really help you with the technology. A better way to use them is not for exam prep for content as much as assessment of readiness. set yourself a 30 minute timer and answer confidently each question within a minute. If you know the answer and can read the entire question within a minute and answer it, then count it for you. If you guess or don't know the answer mark it for study. Guesses, even right ones, count against you. Only right answers that you know count for you. If you can't do 30 questions in 30 minutes if you miss more than 3 questions in that time if you quit from frustration, then you should study more on the concepts.

The Cisco exams are tough because they require to you to be right, timely and not guess but know. Yo don't get second chances and you don't get more time, you don't get hints to the answers from reading the question multiple times.

Let me know if you have any additional questions!

Ronnie,

Thanks for your quick reply! On a Saturday too, thank you. I gotta say i was feeling very confident with the practice exams on ITPro.TV for CCENT scoring consistently 85% and grasping most concepts well. I figured with a little more review my scores would be higher and I'd be ready to test. I will try and find the IPv6 multicast address question I ran across and post it here soon for more context.

As for IP helper, I was just curious if you thought you'd see this more detailed config feature included on the CCENT exam. I have configured DHCP on multiple 2911 routers and configured the basics like default router, DNS server, and the exclusion range for IPv4 scopes... I know you did cover DHCP reservations for single machines as well as DHCP options, perhaps it would be good for me to go back and make IP helper work in the lab just in case.

As for VLSM I appreciate you letting me know I won't probably see this until ICND2. Is this topic something you and Don cover in the CCNA course more closley.? I'll see if I can find the question that broke my brain from this other site and post it. Even with my familiarity with subnettting (I've spent a bunch of time here) it made zero sense to me. Thanks again.

-Adam

Still hunting for that VLSM question, but here was that IPv6 multicast question that threw me for a loop.

What is the destination address of a router solicitation packet?
A. FF02::2
B. FF02::A
C. FF02::9
D. FF02::6
E. FF02::1
F. FF02::5

I am thinking the answer is FF02::2..

@Adam-Tyler said in CCENT 100-105 test prep:

Still hunting for that VLSM question, but here was that IPv6 multicast question that threw me for a loop.

What is the destination address of a router solicitation packet?
A. FF02::2
B. FF02::A
C. FF02::9
D. FF02::6
E. FF02::1
F. FF02::5

I am thinking the answer is FF02::2..

That is the correct answer. The key is understanding out of all the FF02::X answer provided why this is the correct one. The two obvious choices are the ::1 and ::2 options but why? It has to do with who are you trying to contact here. The ::1 address is a solicitation message message for all nodes possible and then the ::2 option is to reach all routers. Since this calls out the router solicitation, you would choose A.

check out details: https://tools.ietf.org/html/rfc4861#page-57

@Adam-Tyler said in CCENT 100-105 test prep:

Ronnie,

Thanks for your quick reply! On a Saturday too, thank you. I gotta say i was feeling very confident with the practice exams on ITPro.TV for CCENT scoring consistently 85% and grasping most concepts well. I figured with a little more review my scores would be higher and I'd be ready to test. I will try and find the IPv6 multicast address question I ran across and post it here soon for more context.

As for IP helper, I was just curious if you thought you'd see this more detailed config feature included on the CCENT exam. I have configured DHCP on multiple 2911 routers and configured the basics like default router, DNS server, and the exclusion range for IPv4 scopes... I know you did cover DHCP reservations for single machines as well as DHCP options, perhaps it would be good for me to go back and make IP helper work in the lab just in case.

The key to acing the CCENT exam and cisco exams in general is practice with the equipment and mastery with the concepts.

As for VLSM I appreciate you letting me know I won't probably see this until ICND2. Is this topic something you and Don cover in the CCNA course more closley.?
Yes, we do cover it more in depth. You'll need to understand the need for the VLSM before doing trying to implement it.

I'll see if I can find the question that broke my brain from this other site and post it. Even with my familiarity with subnettting (I've spent a bunch of time here) it made zero sense to me. Thanks again.

VLSM normally throws everyone off just as subnetting with Class A and Class B addresses.

So here's a real world scenario, You move to a new building and get another ISP provider. The ISP assigns you 32 IP addresses 209.251.131.96/27. You need to reserve 16 addresses for your company and divide up the remaining 16 addresses for tenants in your building. One tenant needs 5 addresses and each of the other tenants need point to point networks. You need to create the network for the tenant requiring 5 addresses. Which of the following network would meet that requirement and still have point to point networks.

This is what variable length subnetting allows you to do.

-Adam

Thanks for the VLSM exercise.. My work shown below, and no subnetting calc!!

Subnet 1 for company with 16 addresses.. (Well, a little confusing because it looks like only 14 usable.)

1111|0000 - /28
0110|0000 - .96 ID
0110|0001 - .97 First
0110|1110 - .110 Last
0110|1111 - .111 Broadcast

Subnet 2 for tenant with 5 address requirement.. 8 addresses, 6 usable.

11111|000 - /29
01110|000 - .112 ID
01110|001 - .113 First
01110|110 - .118 Last
01110|111 - .119 Broadcast

The ramaining subnets would be cut up into /30's for point to point which would allow for 2 addresses per network moving forward. The first of which is listed below. IE... CSU/DSU cards directly connected.

111111|00 - /30
011110|00 - .120 ID
011110|01 - .121 First
011110|10 - .122 Last
011110|11 - .123 Broadcast

How did that look? On the right track? I need more practice, this probably took me 15 minutes or so to do manually. Hopefully it was accurate.

@Adam-Tyler said in CCENT 100-105 test prep:

Thanks for the VLSM exercise.. My work shown below, and no subnetting calc!!

Subnet 1 for company with 16 addresses.. (Well, a little confusing because it looks like only 14 usable.)

1111|0000 - /28
0110|0000 - .96 ID
0110|0001 - .97 First
0110|1110 - .110 Last
0110|1111 - .111 Broadcast

Subnet 2 for tenant with 5 address requirement.. 8 addresses, 6 usable.

11111|000 - /29
01110|000 - .112 ID
01110|001 - .113 First
01110|110 - .118 Last
01110|111 - .119 Broadcast

The ramaining subnets would be cut up into /30's for point to point which would allow for 2 addresses per network moving forward. The first of which is listed below. IE... CSU/DSU cards directly connected.

111111|00 - /30
011110|00 - .120 ID
011110|01 - .121 First
011110|10 - .122 Last
011110|11 - .123 Broadcast

How did that look? On the right track? I need more practice, this probably took me 15 minutes or so to do manually. Hopefully it was accurate.

Yep that's the idea! the key here is think additional questions about a site's needs or why the connectivity isn't happening. Yeah, the problem I gave you would take a longer than a minute, granted. Good work. But the key for the exam is to think of what types of the questions from something like this you could answer within a minute. For example:

1. Which of the follow addresses would be in the /28 subnet?
2. with the info in the diagram, why is the point to point network between Seattle and NY not working?
3. What is the broacast address of the /29 address spaces?
4. What is the first viable address of the /29 address spaces?

thing like this are very real world type of problems and you might need to know to troubleshoot or create a space for a new tenant or establish what equipment would you need to place the addresses.

hope this helped!

Great Ronnie. Thank you. I never did come across that VLSM question that I originally was trying to post about, but I think we've covered the topic sufficiently. Really appreciate it.

One follow up to this, I ran across a question asking about a "block" size that I wasn't able to answer immediately. Can you define block size for me as it applies to a subnet mast? The question read like this:

Which statement is true about the subnet masks /12, /20, and /28?

A. They all have the same number of network bits.
B. They all have the same block size of 16.
C. They all create only 16 subnets.
D. They all have the same number of host bits.

So I have been through subnetting, VLSM, and Wildcard Mast (bits), and block size in this context didn't make sense to me.. I think of block size as the number of addresses included in a given network. Ie, subnet ID all the way up to broadcast address. This generally relates to how many hosts can reside in a given network rather than how many networks can be created.

So the way I have devised a method of figuring out how many hosts can reside in a given network is simply taking 2 to the power of host bits. For example:

(I know you know how, just showing my thought process here.)
a /29 network leaves 3 host bits, and 2 to the power of 3 = 8.. Deduct 2 for ID and password you get 6 usable addresses.

All that being said, the answer to the question above was listed as "B", and if true it blows away my thought above about block size. Because a /12 has 1048574 hosts per network, a /20 has 4094, and a /28 has 14..

The only way I was able to come up with a number 16 for these 3 CIDR notations (/12, /20, /28) was by focusing just on the octet they resided in and using my same "to the power of" process for the network bits.. For example:

/12 - 11111111.1111|0000.00000000.00000000, 4 network bits in the 2nd octet. 2 to the power of 4 = 16.
/20 - 11111111.11111111.1111|0000.00000000, 4 network bits in the 3rd octet. 2 to the power of 4 = 16
/28 - 11111111.11111111.11111111.1111|0000, 4 network bits in the 4th octet. 2 to the power of 4 = 16

But I am not sure if this was just a happy coincidence.. Or why the "block" size would focus on the octet specifically... Help!

Ps.. This probably could be a different post entirely. Let me know if you'd like me to break it out.

-Adam

@Adam-Tyler,

The answer is C.

Remember that in subnetting, you have 3 "portions" of the IP address:

• Network Block (this is normally the default Classful A, B and C blocks)

• Host bits

• Subnetted bits (These are borrowed bits from the Host ID side) so each of these networks have the same 4 bits as you've pointed out. So each one of these will only create 16 networks with differing number of hosts per network.