need to know the subnets for this network id

[amralrazzaz]

i need to know the subnets for this network id 

10.246.0.0/20 ?

and what is the prefix numbers for each network inside this network id ?

thanks

[paul driver]

check here

[amralrazzaz]

may i know what is the prefix number for each network id from 0 to 15 ? it like below :

shall i use it like this or the prefix number for each id should be how much ?

10.246.0.0/??

10.246.1.0/24

10.246.2.0/24

10.246.3.0/24

10.246.4.0/24

10.246.5.0/24

10.246.6.0/24

10.246.7.0/24

10.246.8.0/24

10.246.9.0/24

10.246.10.0/24

10.246.11.0/24

10.246.12.0/24

10.246.13.0/24

10.246.14.0/24

10.246.15.0/24

[Martin L]

network id is 10.246.0.0. Length /20 which is mask 255.255.240.0, give u size of 4094 hosts, Range of hosts 10.246.0.1 to 10.246.15.254, B-cast 10.246.15.255

[amralrazzaz]

may i know what is the prefix number for each network id from 0 to 15 ? it like below :

shall i use it like this or the prefix number for each id should be how much ?

10.246.0.0/????

10.246.1.0/24

10.246.2.0/24

10.246.3.0/24

10.246.4.0/24

10.246.5.0/24

10.246.6.0/24

10.246.7.0/24

10.246.8.0/24

10.246.9.0/24

10.246.10.0/24

10.246.11.0/24

10.246.12.0/24

10.246.13.0/24

10.246.14.0/24

10.246.15.0/24

[Martin L]

that's OK because of /24 which marks first 3 octets are network id; That gives you 254 hosts per each /24.
10.246.0.0/24 as well.
10.246.1.0/24, and so on till 10.246.15.0/24 or all the way up to 10.246.255.0/24.

correction: your /20 range end at 10.246.15.0/24

[amralrazzaz]

so my network id 10.246.0.0/20 including all what i mentioned with /24 from 0 till 15 ?

am i correct :) and thanks

[Martin L]

Yes, you are correct; sorry I forgot that initially you start with /20
your range ends on 10.246.15.0/20, some1 else's begins at 10.246.16.0/20.
btw. you have split your /20 section into equal part of /24 but you could apply VLSM technique to use various ranges (when u have such needs). i.e take 10.246.15.0/24 and split into smaller parts like 10.246.15.0/25 or 10.246.15.0/26, and so on. you can find videos explaining vlsm on youtube.

[amralrazzaz]

thanks for your reply its very useful to me , may i ask you if the below is fine to use in my network 

just another question ,, in general can i use /23 instead of /24 or 25 or 26 or what ever ? 

i need to confirm that this schedule  is correct please :) ? thanks

note: i just need 5 or 6 networks for vlans only and no need for make smaller range from the networks id 

network ID 10.246.0.0/20

10.246.0.0/24
10.246.1.0/24
10.246.2.0/24
10.246.3.0/24
10.246.4.0/24
10.246.5.0/24
10.246.6.0/24
10.246.7.0/24
10.246.8.0/24
10.246.9.0/24
10.246.10.0/24
10.246.11.0/24
10.246.12.0/24
10.246.13.0/24
10.246.14.0/24
10.246.15.0/24

[Martin L · Accepted solution]

Yes, all /24 you listed are OK. from 10.246.0.0/24 to 10.246.15.0/24 are correct and fit into 10.246.0.0/20.

example of VLSM with your /24 ranges:
You can use /25, /26, up to /30 but ranges will be different. trade off is getting more networks for smaller number of Hosts. for example; take 10.246.15.0/24 and make it /25. 1st network id will be 10.246.15.0/25, 2nd will be 10.246.15.128/25 - both fit into 10.246.15.0/24. Those 2 give u 126 host each
i.e #2, take 10.246.14.0/24 and split into 10.246.14.0/26; 1st network id 10.246.14.0/26, 2nd 10.246.14.64/26, then 10.246.14.128/26, then -last one-10.246.14.192/26. Host max per each is 62.

[Martin L]

oh, do you only need 5 or 6 networks from 10.246.0.0/20 ?

[amralrazzaz]

yes maybe up to 10 vlans , and if it is like this so i can use what i share above all /24?? correct ?

and regarding what u said just to share my understanding that all networks will be same as below :

10.246.0.0/24
10.246.1.0/24
10.246.2.0/24
10.246.3.0/24
10.246.4.0/24
10.246.5.0/24
10.246.6.0/24
10.246.7.0/24
10.246.8.0/24
10.246.9.0/24
10.246.10.0/24
10.246.11.0/24
10.246.12.0/24
10.246.13.0/24
10.246.14.0/24
10.246.15.0/25
10.246.15.128/25

[Martin L · Accepted solution]

Yes, that is fine;
10.246.0.0/24
. . . . .
10.246.13.0/24
10.246.14.0/24
10.246.15.0/25
10.246.15.128/25

and if you take 10.246.14.0/24 and make it /26, you will have
10.246.0.0/24
. . . . .
10.246.13.0/24
10.246.14.0/26
10.246.14.64/26
10.246.14.128/26
10.246.14.192/26
10.246.15.0/25
10.246.15.128/25