VLSM Practice Questions...

mattipler

Can anyone point me in the direction of a good source of variable length subnet mask questions... I've had a look on the t'internet and have only found the odd one or two questions dotted about the place. I understand the concepts completely and just need to polish off applying VLSM's quickly and accurately before I put in for the 801 in a few weeks.

Cheers guys.

Matt

Netstudent

Maybe you could just make up your own. Like pick some random numbers for the amount of hosts you would need in each subnet.

Then use VLSM to contigously allocate the addresses. I haven't seen very many practice questions online that required you to do that.

Like 522, 265, 300, 44, 69, 17, 2,2,2.

Lets say you are given 172.31.0.0 /16 There you go, there is a practice VLSM question.

mattipler

I had considered doing that but i'm 100% confident in my ability to do it correctly so would be useful to have a some kind of exam engine.

Netstudent

I understand...Well hope you find something.

mattipler

cheers m8

ehnde

Sorry to revive an old thread, but I'm wondering the same thing as the OP now....

I know about subnettingquestions.com - Free Subnetting Questions and Answers Randomly Generated Online and subnetting.org - Free Subnetting Questions and Answers Randomly Generated Online but what about VLSM? It's been over 3 years since this thread was started. Maybe in the mean time someone has created such a site?

johnwest43

subnetting.org does have vlsm questions.

mella060

Theres a few on this site...

Cisco 5 Exercises

ehnde

johnwest43 wrote: »

subnetting.org does have vlsm questions.

I haven't seen any there. There are plenty of questions like this:

Question: Your company needs to subnet their network to allow for 27 subnets while having as many host addresses available as possible. What subnet mask would you use on the 172.23.0.0 network to accomplish this?

But nothing with VARIABLE length subnets that I've seen so far. Do you just keep answering questions and eventually see one? Or is there a subsection of the site?

miller811

what specifically are you having difficulties with?

Here is an example from a previous post
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The IP scheme that they gave you was a single subnet with 254 host possible.

The example requested
Network A 28 hours
Network B 28 hosts
Network C 14 hosts
Network D 7 hosts
Network E 2 hosts


You need to then break it up into smaller subnets by subnetting......

204.15.5.0 /24
could be broken into two segments of 128 bits by changing the mask to a /25 = 126 usable hosts per subnet
204.15.5.0 /25 204.15.5.0 - 204.15.5.127
204.15.5.128/25 204.15.128-204.15.5.255

it could also be broken into 4 subnets by starting out with a /26 mask = 62 usable host/subnet
204.15.5.0 /26 204.15.5.0-204.15.5.63
204.15.5.64/26 204.15.5.64-204.15.5.127
204.15.5.128/26 204.15.5.128 - 204.15.5.191
204.15.5.192/27 204.15.5.192-204.15.5.255

it could also be broken into 8 subnets with a /27 mask = 30 usable hosts/subnet
204.15.5.0 /27
204.15.5.32/27
204.15.5.64/27
204.15.5.96/27
204.15.5.128/27
204.15.5.160/27
204.15.5.192/27
204.15.5.224/27

it could also be broken into 16 subnets with a /28 mask = 14 usable hosts
it could also be broken into 32 subnets with a /29 mask = 6 usable hosts
it could also be broken into 64 subnets with a /30 mask = 2 usable hosts

So you take the highest number of host you need per subnet first, 2 of the networks required 28 hosts, so the first 2 subnets would be /27

204.15.5.0 /27
204.15.5.32/27

since the second subnet extends to 204.15.5.63, the starting point for the next subnet would be 204.15.5.64

The next subnet requires 14 hosts, we would use a /28 mask

so 204.15.5.64 /28 = 204.15.5.64-204.15.5-79

the next subnet requires 7 hosts, so we would need to use a /28 mask again
so we would start with the next IP
204.15.5.80 /28 = 204.15.5.80 - 204.15.5.95

the last subnet only requires 2 IP address so we would use a /30 mask
the next IP address is
204.15.5.96 /30 = 204.15.5.96 - 204.15.5.99

Hope that helps

Priston

I'm more interested in ip version 6 vlsm.

ehnde

Not having difficulty, I just appreciate the luxury of random practice questions on sites like subnetting.org. Maybe we should build a VLSM question generator site? haha

Excellent1

Sorry to necro an older thread, but I wanted to share a site I found to practice VLSM, both the implementation and summarization. It's not hard to make your own practice scenarios, but convenience is...convenient. I found this thread while googling for practice examples, so I thought I'd share it here. If this is posted elsewhere, my apologies.

Practice Subnet Skills: Design a VLSM Network