Subnetting - Phone Screen

I just had a phone screen for a network engineer position.

Here was 2 of the questions:

How many host addresses are available in 10.15.1.255 with a subnet of 255.0.0.0

What is the broadcast address for 10.1.0.0 with a subnet of 255.255.255.0

Post your answers please, so we can discuss.

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Comments

MAC_Addy

Easy, 16 million hosts on that subnet.

Broadcast, 10.1.0.255.

johnifanx98

Brain_Power wrote: »

I just had a phone screen for a network engineer position.

Here was 2 of the questions:

How many host addresses are available in 10.15.1.255 with a subnet of 255.0.0.0

What is the broadcast address for 10.1.0.0 with a subnet of 255.255.255.0

Post your answers please, so we can discuss.

hey, buddy, when did you get your CCNA certified?

BTW, the first question looks odd. 10.15.1.255 is not a network address...

oli356

It is an address with that subnet mask though.

10.0.0.1 - 10.255.255.254 is the host range.

Brain_Power

johnifanx98 wrote: »

hey, buddy, when did you get your CCNA certified?

Did I give a wrong answer? NO Did I say that I could not answer these questions? NO

Where is your CCNA? exactly...go back to your developer forums...bro no need for smart ass comments here!

However, looks like you failed to provide a quality answer!

RouteMyPacket

Brain_Power wrote: »

I just had a phone screen for a network engineer position.

Here was 2 of the questions:

How many host addresses are available in 10.15.1.255 with a subnet of 255.0.0.0

What is the broadcast address for 10.1.0.0 with a subnet of 255.255.255.0

Post your answers please, so we can discuss.

Even asking such a question IMO is ridiculous. I immediately knew the answer to the second question, but the first I would of had no clue off the top of my head. In the real world, just use an IP Calc

How did you answer if you don't mind me asking? I'd have simply stated "Ok, second question..that's a /24..broadcast will be 10.1.0.255...now as to the first question..I don't know off the top of my head, a ton" then laughed.

They must have asked such a question just to guage your response, I generally ask certain questions when hiring simply to hear the reaction and response, I assume this to be the same.

mikeybikes

I would have replied:

2^24-2

10.1.0.255

4_lom

Brain_Power wrote: »

Did I give a wrong answer? NO Did I say that I could not answer these questions? NO

Where is your CCNA? exactly...go back to your developer forums...bro no need for smart ass comments here!

However, looks like you failed to provide a quality answer!

He has a valid point Brain_Power.... While his execution of it may have been a bit "jerkish", it is expected that anyone with a CCNA would be able to figure out those questions. No offence, of course.

Prasad Satav

mikeybikes wrote: »

I would have replied:

2^24-2

10.1.0.255

Thats the way to go about it..!! Smart

NetworkVeteran

RouteMyPacket wrote: »

Even asking such a question IMO is ridiculous.

I like these questions. Some room for errors and for determining if a candidate is strong, okay, or clueless in the realm of subnetting.

I don't know off the top of my head, a ton" then laughed.

I would personally characterize that as "okay" and 16 million or (2^24)-2 as "strong".

In the real world, just use an IP Calc

In the real world, someone who relies on an IP Calculator to answer such questions will be either slower or more error-prone than a stronger engineer. What do you do when you can't connect to the Internet, or you have a customer in front of you? Interestingly, I remember this same debate in the school system. "Why do kids need to learn multiplication when there are calculators?"

MAC_Addy

johnifanx98 wrote: »

BTW, the first question looks odd. 10.15.1.255 is not a network address...

Yes it is. With a /8 you can you can have that as a valid host address.

oli356

Brain_Power wrote: »

Did I give a wrong answer? NO Did I say that I could not answer these questions? NO

Where is your CCNA? exactly...go back to your developer forums...bro no need for smart ass comments here!

However, looks like you failed to provide a quality answer!

Calm down..
The "Post your answers please, so we can discuss." in my opinion made me think you didn't know. You can't discuss this as there is only 1 correct answer for each question.

johnifanx98

Brain_Power wrote: »

Did I give a wrong answer? NO Did I say that I could not answer these questions? NO

Where is your CCNA? exactly...go back to your developer forums...bro no need for smart ass comments here!

However, looks like you failed to provide a quality answer!

Brain power, I have no intent to offend at all. I'm just joining the discussion and add some color in my way...