04-20-2020 02:39 AM
Hi everyone I'm studying cisco as a self-taught I came to subnetting. By doing an online exercise, the following happened to me:
What are the subnet mask, first available host address of subnet one (NOT subnet zero), and the maximum number of hosts per subnet for the network below?
You need to allow for maximum number of hosts. Also, you can use subnet zero and the all-ones subnet. RFC 1878
Solved! Go to Solution.
04-20-2020 04:07 AM
04-20-2020 02:48 AM
04-20-2020 03:11 AM
04-20-2020 03:23 AM
what is the source of your question? If you are using some sort of online practice questions then
remember - not all online practice questions are correct.
You might want to ask the course/question author for an explanation why he chooses that answer.
hope this helps
please don't forget to rate helpful posts/solutions
04-20-2020 03:31 AM
04-20-2020 03:51 AM
ok .. thanks for sharing the source..
they dont want you to use subnet zero (first subnet)
its picking the 1st IP from the 2nd available subnet
04-20-2020 04:03 AM
04-20-2020 04:07 AM
04-20-2020 04:54 AM
04-20-2020 05:15 AM
when they saying subnet-zero its the 1st subnet and all 1s subnet is the last subnet in the range.
for example -
192.168.0.0/27
will give us 8 subnets
192.168.0.0/27 << first subnet bits zero
192.168.0.32/27
192.168.0.64/27
192.168.0.96/27
192.168.0.128/27
192.168.0.160/27
192.168.0.192/27
192.168.0.224/27 << last subnet bits 1s
04-20-2020 08:35 AM
Hello,
@PietroPoliseno27977 wrote:
So when he says: "Also, you can use subnet zero and the all-ones subnet" does it mean that he uses subnet 0 and 1 a single subnet? But in reality it doesn't happen like this or am I wrong?
you have to split the question in two parts.
1- What are the subnet mask, first available host address of subnet one (NOT subnet zero)
---> you already found how to solve this part.
2- the maximum number of hosts per subnet for the network below?
---> The second part has also a note:
You need to allow for maximum number of hosts. Also, you can use subnet zero and the all-ones subnet. RFC 1878.
This note is not related to first part of the question and it doesn't pose any issue/constraint to the number of hosts per subnet which remain 510.
When he says: "Also, you can use subnet zero and the all-ones subnet" means that when you start to address your network you can also take addresses from subnet zero and all ones subnet to maximize amount of hosts used.
In past this practice of excluding subnet zero and all ones subnet from addressing was encouraged but later with time it was declared obsolete.
Best regards.
04-20-2020 04:03 AM - edited 04-20-2020 04:03 AM
to answer your original question -
They asked for 99 subnets.
1st subnet - 177.3.0.0/23 << they want to use the first subnet
2nd subnet - 177.3.2.0/23
177.3.2.1 is the 1st ip in 2nd subnet
BTW - it looks like a pretty good practice site :) I have not come across anything similar
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