Question on subnetting?

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I will provide the Question, Answer, & explanation then I would like someone to please tell me how the heck to figure this out if I run into it on the test.

Q. You are the administrator of a Windows 2000 network. Your network has 1,900 hosts. Your network requires internet connectivity. Aside from the connection to the internet, your network is not routed. Your ISP assigns you the following eight network addresses:

192.24.32.0/24
192.24.33.0/24
192.24.34.0/24
192.24.35.0/24
192.24.36.0/24
192.24.37.0/24
192.24.38.0/24
192.24.39.0/24

You want to minimize the complexity of routing tables on the network while maintaining internet connectivity for all hosts. Which subnet mask should you configure to meet these goals?

A. 255.255.240.0
B. 255.255.248.0
C. 255.255.252.0
D. 255.255.254.0
E. 255.255.255.0

Explanation:
The answer is B because there must be 1,900 clients on the subnet. At least eleven bits must be used for these 1,900 hosts, since 2**11=2048 and not 10 bits since 2**10=1024. This leaves 21 (32-11) bits for the subnet mask.
Subnet mask in binary: 11111111.11111111.11111000.00000000
Subnet mask in decimal: 255.255.248.0

Thank you in advance,
TJ2004

 

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Hi and welcome. I'd love to answer your questions, but it's Friday night, I've had a long week and I'm tired. My brain doesn't subnet well when I'm tired. I'll do the next best thing. I'll refer you to the site that I used to teach me how to subnet when I was studying for my CCNA. It's called learntosubnet and it's great. It has everything you'll need to learn how to subnet pretty quickly and in your head. For a very small fee, you can purchase the content of site on a CD so you don't have to be online to study. When I wake up tomorrow, I'll give your question a fair crack (I'm about 7 hours behind forum time...live in the U.S.)

I do want to know one thing first...where did your question come from?

See you later.

 

My question came straight from the Microsoft MCSA 70-216 QAE from Testking.com.
Thanks for the link, I've actually been there and I still can't hammer this question out...Do you have any recommendations on study materials??

 

TJ, IMHO TestKing.com are a braindump site.

My advice for whats its worth is throw them in the bin and learn the material. I will also say that I personally won't be willing to give anyone help if I'm aware they are using braindumps as using braindumps is cheating and de-vaules the certs everyone holds nuff said

If you have a legitimate question that you have setup in a lab ( IMHO this is the best way to learn the material) or don't understand a concept from one of the study books, feel free to ask, but please give detailed info as to where it comes from. I and others will be willing to guide/help you!

 

Where do I get IMHO? and what the heck is it??
How about learning through a product called www.selftest.com software??
...and what study software/tool would you recommend??
BTW I've tried transcender and MCSA readiness review and took the test for 70-216 and barely missed passing, so what would you suggest that is "politically correct (non-braindump)"???

 

IMHO = In My Humble Opinion

mate, if you only just missed the mark, dont worry about it, your doing things right, you just need to try a little harder, hell perhaps it was just a bad day, i would be concerned had you scored 50% or lower, but with a 'almost' passed, your on the right track, just keep doin what your doing, brush up on the things your not hot on (like subnetting)
the key is practice!

memorize the 'magic' table as our CCNA instructor called it, to the point that you can draw it down on paper as soon as you walk in the exam room (basic maths may be required) once thats down you can rest at ease and have an easy reference when a subnetting question pops up

 

in response to Japes, firstly try give the guy a break, he did take the time to ask US for help, lets not show him the door so hastely, sure we all hate braindumps, but thats not what de values the certs to be honest
what de values them is the fact they are pretty much an industry standard for an entry level position, meaning they are a dime a dozen
i cant count the ammount of jobs that vanish from my jobserve search if i type 'and not mcse' in the search field

while the industry demands it as a base requirement for the majority of roles, it will continue to be oversubscribed by people who pass the test just for the card, if you read the description of what an MCSE is supposed to be able to do, i can assure you 90% of mcses worldwide could NOT meet those criteria, braindumps are only useful to a certain type of person anyway, not everyone can use them, and cramming thousands of pages into memory from a MS Press book is just as pointless, but its required for most microsoft exams, they are not based purly on the text subject, but on your ability to reason with the questions, chop out the paragraph or two of useless information, and still answer the question in under 60 seconds

to this date no other cert i have taken part in asks questions in this manner, i've used Windows NT for almost 8 years, and I could not walk into a MS exam and pass without first reading a book, i could walk into a Cisco exam and pass, they base there exams on facts and knowledge of the subject

hope that makes sense lol
bottom line., dont put too much faith in an MS cert

 

Phoenix: Thank you for explaining what IMHO means. I'm not up on the shorthand chat lingo yet, but I'm learning. I also want to thank you for your input on this question. I really appreciate your consideration of my situation and the fact that I don't want to "cheat" on any tests. I just want to know what the best way to study besides trying to memorize pages out of a book or using Trancender or MCSA readiness reviews which turned out to be not adequate enough for me to get a firm understanding about what MS wants to pass this test.

Japes: I understand your frustration with "braindumps" and I didn't mean to offend you or anybody else. I was just answering a question honestly about where I saw this question/answer/explanation I had trouble with and I also wanted anybody out there to guide me to a study product or tool(s) to help me get a firm understanding about what is required from this test since I've already failed it once. As everybody who has taken this test knows, it is not cheap.

 

mmmmmm thought about this one long and hard......

TJ

For me IMHO = In My Honest Opinion - good TLA (three Letter Acronym) site

I'm assuming you've never setup a lab and expect all the answers to come from a Q&A. I base this on your change from one Q&A to another Q&A. Yes it is posiable to pass all the exams this way, but hands on is the best policy as I said on my reply above and also said in the here in the Study Material thread, which was also in reply to a similar question about this exam (I appriciate you may not have seen that reply).

You say you've taken and failed the exam, therefore you should know the sorts of questions you obviously didn't know and the ones you weren't sure of. Study those area’s, before thinking about a re-sit.

Build a 2 PC w2k advanced servers lab (You can get a CD from MS or maybe even download the trial version). Do a Humpty Dumpty ie play with it, break it, put it back together. Find out why “it didn't/does” work. This will not only help on the exam but on the job. Any of the Trancenders/selftest software type Q&As are only as good as the follow up you do. IMHO they are not the answer to on the job problems/solutions nor are they a complete answer to the exam.

MS Online w2k Server docs is a good resource. Not to easy to find at the MS site. Talking of which, how often do you use the online MS KB (knowledgebase) if you don't I'd suggest you start doing so, again a wealth of info.

You say you still don't understand the original question..... the answer maybe: It builds on subnetting and is in fact a "Supernetting/CIDR" question (Something not even mentioned in the answer ). In fact the answer only explains what has happened to the subnet mask and not why it has been done or what rules need to be observed when supernetting. Try doing a search in google and see what answers you can get.

 

Actually I have setup a lab when 2000 server first came out, but haven't had the capability or the time to set one up in my current employer. How can I search (keywords) for this Study Material thread you are talking about?

The problem with the fact that I've taken and failed the exam is I don't know which of the questions that I obviously didn't know and the ones I wasn't sure of. Otherwise, I would study those areas before I retook the test.

I'm not able to build a 2 PC w2k advanced servers lab with my current work situation & time. The ironic thing about this is that I've built and maintain a 2kserver on the job and I still failed. What is the answer to on the job problems/solutions/complete answers to the exam keeping in mind that I don't have the capability to build a lab.

I have a burned CD of MS Online w2k Server docs that I've tried to use with no luck. I actually have a subscription of Technet & I utilize online MS KB (knowledgebase) with no luck there either.

As far as that question, I received a response that breaks it down like this (which I am starting to understand a little better):

We are dealing here with supernetting, not subnetting

The first 2 octets are the same so no worries there
255.255.240.0
255.255.248.0
255.255.252.0
255.255.254.0
255.255.255.0

The third octet:
32 0010 0000
33 0010 0001
34 0010 0010
35 0010 0011
36 0010 0100
37 0010 0101
38 0010 0110
39 0010 0111

As you can see the first 5 bits are the same so we need to place this in the network mask [mark the terminology]

1111 1xxx where x is do not care bit

now the network mask becomes:
255.255.1111 1000.0 [not good but see the binary], we convert this third binary octet to decimal:

128 64 32 16 8 4 2 1
1 1 1 1 1 1 0 0
128 + 64 +32 +16 +8 = 248

So the network mask becomes 255.255.248.0

 

mmm I thought I had, by saying come back with legitimate questions. Maybe I didn't word it very well.

Certs.......
I agree that the industory has set the bench mark, but is that a cause or effect of the popluarity of MS certs or is it more liekly a way of trying to weed the numbers down by the HR types, because of the market being overloaded with people trying to get into IT!

I also agree that 90% of MCSE's can't do what the criteria says, only because we use 20% of the server 80% of the time and the 80% we use 20% of the time and that usually only needs to be setup once.....

So the MS exams are asking you to know stuff you don't already know but the Cisco exam doesn't..... May seem like a cheap shot, but I'm making a point. I think it comes down to how much you use the equipment, before trying to take the exam, that is the real difference here. From my exprience what I've said above (about 20% used 80% of the time) is true for MS and Cisco.

A collegue of mine hasn't taken the DBA exams but probably could as he's been working with SQL for about 5 years now and maintains several servers. He holds the MCSE so it would only be 2 exams and I think he could pass them easily.
I passed the 218 exam without trying, the 217 was reasonably easy and the training course wasn't difficult for me, could posiably have taken this one without much study. However the 216 was much more of a challange both the course and the exam, why.... I think becuase I didn't use many of the aspects of the material all that often. I can't say how well I did them as I didn't get a score, but that was my feel afterwards.

I see several things that come into play here.

• 1 It depends on how much you actually work with the equipment in that area
  2 What sort of company you work for (CCNP's don't tend to work for a small 100 client network, no need, but MCSE's do)
  3 Cisco is more focus'ed on an area (networking), where as MS is much more diverse (not nessisarily a good thing as I think they are overly diverse ).

Agree but would make than ANY CERT. They are all just a peice of paper, it is the knowledge that the holder has that is useful, and if we knew that all the holders of the certs hadn't dumped there way through they would all be seen in a better light..... Hense why a holder of the CCIE is still viewed in a very good light, you can't dump that practical.

 

Japes, thanks for your detailed response mate
Actually I use windows alot more than I use cisco stuff (once my routers/firewalls are set up they very rarely need playing with) infact i had a real challenge re learning PIX at my last place because i hadnt used since i set up a network 18 months prior lol, it didnt neet touching.

On the other hand, a windows network tends to need lots of tweaking/touching/playing with etc on a daily basis, so should come with alot more exposure

the problem with subnetting is you need to know the math/basics, you cant go roll out a 1900 node network, deploy a ip scheme and go 'darn, run out of addresses, note to self, use the next range up' like you could in a normal 'practical lab' so it really DOES come down to theory and such

as for your DBA friend, good luck to him if he decides to sit them, i hear those along with the security exams are microsofts hardest exams (this was from an MCT who tought all three not just an MCSE who didnt understand SQL lol) my point is that the way MS exams are written requires some understanding of the 'microsoft' answer, not always the 'practical/in real life answer' where as the majority of other exams i have done merly want generic fact answers

I wouldnt go so far to say dont put faith in ANY CERT, i opened up my way into this industry with certs and no formal qualification or experiance, and im cut a piece out for me with more certs and still no formal qualifications, now i have got the the pont where i can take a formal qualification BASED on my experiance and certs, so i think they are important, and they do show a level of knowledge if you earnt it,
certs are not always just for employers, they are for ourselves, being certified to a certain level gives me alot more confidence that I DO have what it takes to meet a perticular task, even if I have never done it before, because i have practiced, and worked with the technology, and I think being confident about performing a task is just as important, becuase we have never done everything 'in a real situation' there will always be something we need to do thats new to us

 

I haven't posted for a while I must confess, and whilst its great fun seeing all the comedy on these forums these days, it was initially refreshing to see someone asking for help on a genuinely difficult topic.

However, and I'm likely to get flamed for what I'm about to say, I have got to say I am disappointed in the responses from obviously knowledgeable people. I would hasten to add these comments are not directed at any one individual.

As far as I can see, and as far as I know, the spirit of these forums should, and historically have always been, helping out the guys who dont have the knowledge but are keen to learn. From my personal experience, a "proper" discussion helps invaluably, rather than A) point people to other sites - although this can have value - and B) more disappointingly, people seem to adopt the 'posturing approach' i.e. "you should do this, or I dont think you should do that, I'm an expert" which really doesnt help anyone.

Sorry if anyone takes offence to this, but I'm afraid I just had to say it....

 

Looks like you found your answer. It is possible to either combine subnets which is called supernetting or to subnet a subnet...that is to subdivide a subnet to create several subnets. The whole thing can be a real head scratcher and ironically, it will all start to go away when IPv6 is implemented...well, not right away, but eventually.

 

I'm not going to answer your question TJ, because I can't with my current knowledge.
To be honest it's not an area I'm deeply focusing on at the moment, also.

Just read Cartmans response, and have to say I agree wholeheartedly.

Why can't we keep a thread, with a specific subject, to that subject.
For pity sake keep threads on target, to enhance our understanding of concepts.

Let's not introduce areas which although in some respect have an association with the subject at hand, they are not pertaining to the matter at hand.

Think about it.We all have our own associations to things, our own personal experiences and dealing in our own worlds.

When I read the above replies, I think that much of it is inclinations born out of personal endeavours.
There is a propensity towards this type of response, which although clear in your minds, is abstruse and somehwhat tiring to read for me and others.

The deviations and linkages are introduced liberally, causing overwhelm.

Can't we just stick to topic, I know it's a bit boring, but you see I thought this place was about learning.About certification.

I find your talk on some of the above, which is not pertaining tot he matter at hand, completely boring.
No disrespect intended of course, I'm sure it's very interesting to you.Just like if Cartman and I were discussing something.It may be compeltely boring to yourselves, that's fine.I couldn't give a hoot, and neither should you about me finding some of what you say uninspiring and just plain useless to ym needs.

The impression is conveyed that you are more concerned with efficacy, in terms of your own unique perceived completeness, which can't even be gained posthumously.
Let alone in this life.

Ta

 

Hi All

It took me months and months to get subnetting straight in my head. For years I'd enter the numbers and think no more of it as somebody had told me what to type.

Then I wanted to know how to do it and it felt like banging my head against a brick wall till finally the penny dropped. I have heard subnetting explained in more ways than I care to remember for me it worked best using a Class A address (less numbers to worry about).

If you can get your hands on Chpt 5 of TCP/IP for Windows 2000 there is a great table (I have attached an Excel file based on the book).

Work at it - it will make sense.

 

Thank you to Sandy for dragging this subject back ON TOPIC and posting something genuinely useful.

That little excel sheet will be saved, I can tell you.

Good to see the spirit of this place has survived....

 

Thanks for the spreadsheet sandy...