# Idea for a study aid

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• Member Posts: 52 ■■□□□□□□□□
Next question:

Using a standard class B address, what subnet mask would you use to get 300 subnets?
• Member Posts: 52 ■■□□□□□□□□
I thought I'd put out some numbers to convert, I found that doing a lot of these by hand made me a lot faster....

convert the following number sets to binary:
127
32
252
129
14
8
240
243
34
56
77
91
255
81
17
190

convert the following decimal numbers to hexidecimal
900
14
128
72
255
32
716
19
128
77
41
38

convert the following binary numbers to hexadecimal
11111011
00001110
00100000
10010001
10101110
11011011
10001000
10010110
10101111
11000000
• Member Posts: 187
Probably a good idea to time yourself as well - you want to be able to do conversions quickly because they don't give you a lot of time on the exam.
TranscenderMichael (at hotmail.com)
MCSE+I, MCDST, MCDBA, OCP, CCNP, CCDP, CNE, CCSA, Security+, Linux+, Server+, A+
Kaplan IT
Powering Transcender and Self Test Software
Served proudly, USArmy, 98C, '89-'92
• Member Posts: 52 ■■□□□□□□□□
Nobody has anything to add? Maybe some questions problems for us to solve?
• Member Posts: 9 ■□□□□□□□□□
Here's a good one

is this a valid class C IP? why?

192.168.24.59/30
• Member Posts: 2 ■□□□□□□□□□
Next question:

Using a standard class B address, what subnet mask would you use to get 300 subnets?

I hope this is right . . .

Class B:
/25 or 255.255.255.128
2^9 = 512 Subnets (2^8=256 < 300 < 2^9 = 512)
2^7-2 = 126 Valid Hosts
• Member Posts: 9 ■□□□□□□□□□
Deeter wrote:
Next question:

Using a standard class B address, what subnet mask would you use to get 300 subnets?

I hope this is right . . .

Class B:
/25 or 255.255.255.128
2^9 = 512 Subnets (2^8=256 < 300 < 2^9 = 512)
2^7-2 = 126 Valid Hosts

255.255.128.0 =510 subs 126 hosts (if using older ip standards)
• Member Posts: 2 ■□□□□□□□□□
Deeter wrote:
Next question:

Using a standard class B address, what subnet mask would you use to get 300 subnets?

I hope this is right . . .

Class B:
/25 or 255.255.255.128
2^9 = 512 Subnets (2^8=256 < 300 < 2^9 = 512)
2^7-2 = 126 Valid Hosts

255.255.128.0 =510 subs 126 hosts (if using older ip standards)

True, but we're now in the brave new world of ip subnet-zero. (Or so sayeth Todd Lammle.)
• Member Posts: 9 ■□□□□□□□□□
True, but we're now in the brave new world of ip subnet-zero. (Or so sayeth Todd Lammle.)[/quote]

I don't know if the CCNA exam honor ip subnet-zero, but the CCNP does
• Member Posts: 52 ■■□□□□□□□□
From the feedback from friends, they do not. It seems that 2^2-2 is still in practice for the ccna exam.
• Member Posts: 9 ■□□□□□□□□□
From the feedback from friends, they do not. It seems that 2^2-2 is still in practice for the ccna exam.

I do think there are a couple of them depending on which exam you receive, but the term 'subnet-zero' will be specified.
• Member Posts: 187
Best bet is to expect either. Most likely, they won't ask you to choose between two "possibly correct" choices.
TranscenderMichael (at hotmail.com)
MCSE+I, MCDST, MCDBA, OCP, CCNP, CCDP, CNE, CCSA, Security+, Linux+, Server+, A+
Kaplan IT
Powering Transcender and Self Test Software
Served proudly, USArmy, 98C, '89-'92
• Member Posts: 52 ■■□□□□□□□□
Best bet is to expect either. Most likely, they won't ask you to choose between two "possibly correct" choices.

If they didn't that would be the first cert exam I've taken that didn't.
• Member Posts: 187
Best bet is to expect either. Most likely, they won't ask you to choose between two "possibly correct" choices.

If they didn't that would be the first cert exam I've taken that didn't.

*laughing* Well said.

I meant, regarding choosing between subnet-zero and no subnet-zero. heeheehee!
TranscenderMichael (at hotmail.com)
MCSE+I, MCDST, MCDBA, OCP, CCNP, CCDP, CNE, CCSA, Security+, Linux+, Server+, A+
Kaplan IT
Powering Transcender and Self Test Software
Served proudly, USArmy, 98C, '89-'92