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Offline Dr David Thork

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Re: How to Subnet, an Example
« Reply #20 on: August 10, 2021, 08:50:36 AM »
The worst thing about this shit is that everyone explains it a little bit differently. It's not even that difficult but there are 1000 explanations for it. I'm taking the Network+ next week and I'm just going to memorize the number of hosts and subnets for the /25 - /31 networks. Well, Get fucked CompTIA, if I have to do this IRL I'll just use a subnet calculator lmfao. What is this, 2001?

Also I tried to do your example in my head without looking at the answer and got to 16 subnets with 14 hosts in each, but class Cs are ez. If they ask me abnoout class A or B networks I'll just turn my computer off.
You should come to the UK. We now have a system where no one ever has to go to class and 50% of the students get an A* or A.
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Offline xasop

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Re: How to Subnet, an Example
« Reply #21 on: August 10, 2021, 10:32:39 AM »
The worst thing about this shit is that everyone explains it a little bit differently. It's not even that difficult but there are 1000 explanations for it. I'm taking the Network+ next week and I'm just going to memorize the number of hosts and subnets for the /25 - /31 networks. Well, Get fucked CompTIA, if I have to do this IRL I'll just use a subnet calculator lmfao. What is this, 2001?
It's literally just powers of 2. It's more work to memorise it than it is to just figure it out from first principles in the exam, provided you understand the principle.

Also I tried to do your example in my head without looking at the answer and got to 16 subnets with 14 hosts in each, but class Cs are ez. If they ask me abnoout class A or B networks I'll just turn my computer off.
If you're doing subnetting, you're not using classful networks.
when you try to mock anyone while also running the flat earth society. Lol

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Offline Dr Van Nostrand

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Re: How to Subnet, an Example
« Reply #22 on: August 10, 2021, 11:59:31 AM »
https://www.calculator.net/ip-subnet-calculator.html
https://www.site24x7.com/tools/ipv4-subnetcalculator.html

I asked the instructor why we have to learn to do this when there are calculators to do this.


Instructor
: What if you're trapped on a desert island without your calculator and you have to assign IP addresses across a SOHO network. You would have to come up with the addresses by hand.
Me: But if you're setting up a network wouldn't you have...
Instructor: Shut Up!
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Offline xasop

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Re: How to Subnet, an Example
« Reply #23 on: August 10, 2021, 01:20:27 PM »
I asked the instructor why we have to learn to do this when there are calculators to do this.

Instructor: What if you're trapped on a desert island without your calculator and you have to assign IP addresses across a SOHO network. You would have to come up with the addresses by hand.
Well, yes, that is a terrible reason. A better reason is that you need to be able to reason about what the calculators are doing.

The only thing less professional than not using the tools available to help you is using tools without understanding what they do.
when you try to mock anyone while also running the flat earth society. Lol

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Offline Dr Van Nostrand

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Re: How to Subnet, an Example
« Reply #24 on: August 10, 2021, 03:25:50 PM »
I asked the instructor why we have to learn to do this when there are calculators to do this.

Instructor: What if you're trapped on a desert island without your calculator and you have to assign IP addresses across a SOHO network. You would have to come up with the addresses by hand.
Well, yes, that is a terrible reason. A better reason is that you need to be able to reason about what the calculators are doing.

The only thing less professional than not using the tools available to help you is using tools without understanding what they do.

That is the most correct answer.

Unfortunately for me, I forgot all the subnetting techniques one day after I took the exam.

If I'm stuck on Gilligan's Island without subnet calculating software and I have to assign IP addresses, I'm screwed.
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Offline WTF_Seriously

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Re: How to Subnet, an Example
« Reply #25 on: August 10, 2021, 04:03:41 PM »
The only thing less professional than not using the tools available to help you is using tools without understanding what they do.

Someone here:

https://forum.tfes.org/index.php?topic=18335.0

could learn a lot from this statement.
Distance from Sydney to Perth - We don't know.
There's a mirror floating in the sky - Yup.

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Offline junker

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Re: How to Subnet, an Example
« Reply #26 on: August 10, 2021, 06:27:44 PM »
I forgot how helpful old me was.

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Offline Fortuna

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Re: How to Subnet, an Example
« Reply #27 on: August 10, 2021, 06:33:11 PM »
The worst thing about this shit is that everyone explains it a little bit differently. It's not even that difficult but there are 1000 explanations for it. I'm taking the Network+ next week and I'm just going to memorize the number of hosts and subnets for the /25 - /31 networks. Well, Get fucked CompTIA, if I have to do this IRL I'll just use a subnet calculator lmfao. What is this, 2001?
It's literally just powers of 2. It's more work to memorise it than it is to just figure it out from first principles in the exam, provided you understand the principle.

Also I tried to do your example in my head without looking at the answer and got to 16 subnets with 14 hosts in each, but class Cs are ez. If they ask me abnoout class A or B networks I'll just turn my computer off.
If you're doing subnetting, you're not using classful networks.

Yes, the delineation between classful addressing and CIDR notation is very clear. But that's just how I think about it. Mostly because I've never encountered a network with crazy subnetting before, even at my current job, which has a bunch of LANs across different sites.

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Offline Fortuna

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Re: How to Subnet, an Example
« Reply #28 on: August 10, 2021, 08:24:10 PM »
255.255.255.0 /24
1 subnet, 254 possible hosts

255.255.255.128 /25
2 subnets, 126 possible hosts

255.255.255.192 /26
4 subnets, 62 hosts

255.255.255.224 /27
8 subnets, 30 hosts

255.255.255.240 /28
16 subnets, 14 hosts

255.255.255.248 /29
32 subnets, 6 hosts

255.255.255.252 /30
64 subnets, 2 hosts

255.255.255.254 /31
128 subnets ... no hosts?

255.255.255.255 /32
256 subnets again no hosts?
« Last Edit: August 10, 2021, 08:27:54 PM by Fortuna »

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Offline xasop

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Re: How to Subnet, an Example
« Reply #29 on: August 10, 2021, 08:59:32 PM »
255.255.255.0 /24
1 subnet, 254 possible hosts
It makes no sense to say that a /24 has "1 subnet". What you probably mean is that a /24 can be divided into one /24, two /25s, four /26s, and so forth. But if you start with a /23, you can divide that into two /24s, not one.
when you try to mock anyone while also running the flat earth society. Lol

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Offline Fortuna

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Re: How to Subnet, an Example
« Reply #30 on: August 17, 2021, 02:10:26 AM »
Just passed the Net+ but I was shitting my pants for a few hours before the start time. I studied circuit switched networks for hours and didn't see a single question on it.

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Offline Dr Van Nostrand

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Re: How to Subnet, an Example
« Reply #31 on: August 17, 2021, 01:52:28 PM »
Just passed the Net+ but I was shitting my pants for a few hours before the start time. I studied circuit switched networks for hours and didn't see a single question on it.

* fist bump*

I want to take Security Plus but I'm sure I need to be in to network plus before I try it.

Microsoft has virtual server ISOs ( trial copies) for free download. I'm looking at setting one up in virtualbox to practice on.  I'm guessing that Active Directory is all over the network plus test and I hardly ever use it in my real life.
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Offline junker

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Re: How to Subnet, an Example
« Reply #32 on: August 17, 2021, 03:24:00 PM »
Just passed the Net+ but I was shitting my pants for a few hours before the start time. I studied circuit switched networks for hours and didn't see a single question on it.

Now forget about 99% of N+ and learn some core routing and switching (Cisco is decent for this, just ignore all their proprietary shit like HSRP and EIGRP). Then move straight to AWS and work on Solutions Architect and Advanced Networking. Learn Python while doing the above so you can automate anything on-prem. Lastly, send me a bottle of top-shelf bourbon when you are raking in $200K+/yr after following the aforementioned advice.

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Offline junker

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Re: How to Subnet, an Example
« Reply #33 on: August 17, 2021, 03:30:40 PM »
I'm guessing that Active Directory is all over the network plus test

It isn't.

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Offline Fortuna

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Re: How to Subnet, an Example
« Reply #34 on: August 17, 2021, 03:42:29 PM »
Just passed the Net+ but I was shitting my pants for a few hours before the start time. I studied circuit switched networks for hours and didn't see a single question on it.

Now forget about 99% of N+ and learn some core routing and switching (Cisco is decent for this, just ignore all their proprietary shit like HSRP and EIGRP). Then move straight to AWS and work on Solutions Architect and Advanced Networking. Learn Python while doing the above so you can automate anything on-prem. Lastly, send me a bottle of top-shelf bourbon when you are raking in $200K+/yr after following the aforementioned advice.

That’s almost exactly what I had planned out except for Cisco. And I didn’t know IT salaries went that high.

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Offline Fortuna

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Re: How to Subnet, an Example
« Reply #35 on: August 17, 2021, 03:46:44 PM »
Just passed the Net+ but I was shitting my pants for a few hours before the start time. I studied circuit switched networks for hours and didn't see a single question on it.

* fist bump*

I want to take Security Plus but I'm sure I need to be in to network plus before I try it.

Microsoft has virtual server ISOs ( trial copies) for free download. I'm looking at setting one up in virtualbox to practice on.  I'm guessing that Active Directory is all over the network plus test and I hardly ever use it in my real life.

Not sure exactly what’s on the Sec+, but I’m guessing it’s vendor neutral just like Net+. Like Junker said, there’s no AD at all. I’m assuming Sec+ has some Net overlap so I’d probably do that first. Seems kind of useless to know about security operations without first having at least a broad overview of how networks work.