# Create a Subnetting Cheat Sheet
**URL:** https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222
**Category:** Lessons Discussion
**Created:** [December 29, 2016, 5:13pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222 "2016-12-29T17:13:59Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [December 29, 2016, 5:13pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/1 "2016-12-29T17:13:59Z")
This topic is to discuss the following lesson:
> **[Create a Subnetting Cheat Sheet](https://networklessons.com/subnetting/create-a-subnetting-cheat-sheet)**
>
> Creating your own subnetting cheat sheet helps to quickly answer any subnetting / access-list questions you might encounter on Cisco CCNA / CCNP exams.
---
### Author:  [@talk2seeni](https://forum.networklessons.com/u/talk2seeni)
#### Post date: [October 12, 2015, 4:49pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/2 "2015-10-12T16:49:29Z")
Hi Rene,
Cheat Sheet Table under Step 4 and Step 5 needs some correction. Please revisit and correct , it will be very useful for all of us.
Thanks ,
SV
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### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [October 13, 2015, 6:53pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/3 "2015-10-13T18:53:53Z")
Hi SV,
Thanks, I just fixed a few errors. If you encounter any, please let me know and I’ll correct them.
Rene
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### Author:  [@36lima](https://forum.networklessons.com/u/36lima)
#### Post date: [October 25, 2015, 12:53am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/4 "2015-10-25T00:53:08Z")
Another easy way to get the wildcard value is to subtract the value in each octet in the subnet mask from 255.
Example: 255.255.248.0 subnet mask
1st Octet: **255 -** 255 = 0
2nd Octet **255 -** 255 =0
3rd Octet **255 -** 248 = 7
4th Octent **255 -** 0 = 255
Giving a wildcard mask of 0.0.7.255
---
### Author:  [@nygma2001](https://forum.networklessons.com/u/nygma2001)
#### Post date: [October 25, 2015, 7:03pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/5 "2015-10-25T19:03:44Z")
Hi Rene,
It looks like /25 - /30 were not written in the 4’th octet. That is where the masks should be written, correct?
Thank you,
Kenny
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### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [October 27, 2015, 9:02pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/6 "2015-10-27T21:02:38Z")
Hi Kenny,
Ah I see it now…that’s a copy/paste error, sorry for the inconvenience. It’s fixed now!
Rene
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### Author:  [@hoangtrinh714](https://forum.networklessons.com/u/hoangtrinh714)
#### Post date: [October 12, 2016, 1:50am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/7 "2016-10-12T01:50:13Z")
Hi Rene,
Are you going to talk about Wild Card and Access-List ?
Thanks,
Hoang Trinh
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### Author:  [@hroger](https://forum.networklessons.com/u/hroger)
#### Post date: [March 20, 2019, 7:41pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/8 "2019-03-20T19:41:12Z")
not possible to write all that in the very small whiteboard they will give at the exam. Except when you write it directly on the desk…
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### Author:  [@hroger](https://forum.networklessons.com/u/hroger)
#### Post date: [March 20, 2019, 8:05pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/9 "2019-03-20T20:05:36Z")
and it misses step 1 bis 🙂
after writ down 8 bits, calculate these :
255-1 = 254
254-2 = 252
252-4 = 248
248-8 = 240
240-16 = 224
224-32= 192
192-64 = 128
128-128 = 0
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### Author:  [@maritdelange](https://forum.networklessons.com/u/maritdelange)
#### Post date: [December 16, 2019, 1:22am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/10 "2019-12-16T01:22:30Z")
This is a bit of a silly question.. I’m having the ICND1 exam in 10 days so I have no experience with Cisco exams yet. Do they actually allow this, the creation of the cheat sheet? I thought that you can’t use anything when sitting there?
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### Author:  [@lagapidis](https://forum.networklessons.com/u/lagapidis)
#### Post date: [December 16, 2019, 7:44am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/11 "2019-12-16T07:44:07Z")
Hello Marit
When you go to write the exam, you are given a laminated A4 or letter sized card and a whiteboard marker. After you take a seat at the exam, you can write anything you like on that before or during your exam. It’s there for notes, calculations, or even a motivational quote if you like 😜. So if you remember the logic of the “cheat sheet” you are free two write it down before you begin.
I hope this has been helpful!
Laz
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### Author:  [@maritdelange](https://forum.networklessons.com/u/maritdelange)
#### Post date: [December 16, 2019, 11:18am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/12 "2019-12-16T11:18:26Z")
That is really good to know, I’ll go practice a bit more on the cheat sheet 😉 Thanks!
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### Author:  [@yannick\_libam](https://forum.networklessons.com/u/yannick_libam)
#### Post date: [September 28, 2022, 1:24am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/13 "2022-09-28T01:24:57Z")
That’s brilliant! So much simpler 👏
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### Author:  [@iffy\_jiffy](https://forum.networklessons.com/u/iffy_jiffy)
#### Post date: [February 23, 2023, 9:52pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/14 "2023-02-23T21:52:13Z")
Hi Rene,
If im doing the CCNA exam remotely (at home) on my own laptop, you can only use the “notepad” provided as part of the _exam_ during the _exam_ to write the cheat sheet on. Is this correct? Rules are different to when you to take the exam in person at a venue and you are given a a4/card as opposed to taking the exam remotely. Correct me if im wrong here.
Thanks.
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### Author:  [@lagapidis](https://forum.networklessons.com/u/lagapidis)
#### Post date: [February 26, 2023, 9:31am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/15 "2023-02-26T09:31:21Z")
Hello Irfan
According to the [FAQ found at Cisco’s OnVUE online proctored exam web page](https://home.pearsonvue.com/cisco/onvue), no scratch paper or note boards are allowed during an OnVUE online exam. For this reason, a built-in digital whiteboard can be used for scratch work or note-taking during an exam. Here is a practice whiteboard that’s available to see what it’s like:
[https://home.pearsonvue.com/onvue/whiteboard](https://home.pearsonvue.com/onvue/whiteboard)
You can actually type as well, so if it’s challenging to take notes with the mouse, you can write out your subnetting cheat sheet by typing it out.
I hope this has been helpful!
Laz
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### Author:  [@jordanmalanda4](https://forum.networklessons.com/u/jordanmalanda4)
#### Post date: [December 7, 2024, 2:39pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/16 "2024-12-07T14:39:17Z")
Thank you Rene for this course
i would like to understand, if today I position myself to take my CCNA exam online would need a draft note where could I write my memory aid?
so why isn’t Cisco providing it to us?
with regard to the exercise on the memory aid course could I have more solution on this to refine my understanding
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### Author:  [@lagapidis](https://forum.networklessons.com/u/lagapidis)
#### Post date: [December 10, 2024, 6:18am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/17 "2024-12-10T06:18:08Z")
Hello Jordan
When taking the CCNA exam online, you are not allowed to use physical paper or pen for note-taking or memory aids. This is done to ensure that no unauthorized materials are used. However, Cisco does provide you with an on-screen whiteboard feature during the exam that you can use to make notes or aid your memory.
Concerning ways in which you can study and aid your memory, Rene has the following lessons available:
- [How to study Cisco and Networking](https://networklessons.com/miscellaneous/how-to-study-cisco-and-networking)
- [How to take networking notes](https://networklessons.com/miscellaneous/how-to-take-networking-notes)
You can also take advantage of the practice exams that NetworkLessons has available for testing your understanding:
> **[Networklessons Exams - NetworkLessons.com](https://networklessons.com/networklessons-exams)**
>
> Networklessons offers practice exams for CCNA, CCNP, and specific topics/protocols. Use them to see if you have any knowledge gaps.
Let us know if there are other ways we can help!
I hope this has been helpful!
Laz
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### Author:  [@mx.linx76](https://forum.networklessons.com/u/mx.linx76)
#### Post date: [October 17, 2025, 10:39am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/18 "2025-10-17T10:39:07Z")
Hi, this is my answer to the question below the chapter. Would appreciate any feedback.
What’s the subnet mask of the /19 CIDR notation?
255.255.224.0
How many addresses does a network with subnet mask 255.255.255.224 cover?
32
Are 10.10.10.96/23 and 10.10.10.140/23 in the same subnet? - Yes
network address 10.10.10.0
first ip address 10.10.10.1
last ip address 10.10.11.254
broadcast address 10.10.11.255
Configure an access-list that blocks traffic from 172.16.1.0/17
0.0.127.255
Thank you,
Kader
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### Author:  [@davidilles](https://forum.networklessons.com/u/davidilles)
#### Post date: [October 18, 2025, 11:33am UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/19 "2025-10-18T11:33:45Z")
Hello akader.
> What’s the subnet mask of the /19 CIDR notation?
> 255.255.224.0
That’s correct! /19 is basically 19 1s in a row, so 11111111 11111111 1110000 00000000 which results in 255.255.224.0
> How many addresses does a network with subnet mask 255.255.255.224 cover?
> 32
Correct. A /27 subnet provides 32 addresses in total with the lowest one being reserved for the network and the highest one being reserved for broadcast.
> Are 10.10.10.96/23 and 10.10.10.140/23 in the same subnet? - Yes
> network address 10.10.10.0
> first ip address 10.10.10.1
> last ip address 10.10.11.254
> broadcast address 10.10.11.255
Correct! I don’t think I need to comment any more on this.
> Configure an access-list that blocks traffic from 172.16.1.0/17
> 0.0.127.255
Correct. Along with the network, it would be 172.16.1.0 0.0.127.255.
Let us know if you have any further questions!
David
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### Author:  [@mx.linx76](https://forum.networklessons.com/u/mx.linx76)
#### Post date: [October 18, 2025, 1:26pm UTC](https://forum.networklessons.com/t/create-a-subnetting-cheat-sheet/1222/20 "2025-10-18T13:26:01Z")
Thank you,
David