# Subnetting Problem

Hi,

10.0.18.0/16

regards

Neo

Neo

with a /16 ie 255.255 then that is a host address.

ie. 10.0.18.0 255.255.0.0 = 10.0 is the network, everything else is host addresses.

If it was 10.0.18.0/24 then yes that would be a network.

Jon

Overall Rating: 4 (1 ratings)

## Replies

Jon Marshall Thu, 04/09/2009 - 10:42

Neo

10.0.18.0/16 = 10.0.18.0 255.255.0.0

This means the network is 10.0 and so the broadcast address would indeed be 10.0.255.255.

Jon

Hi,

Subnetting is being used over here

and netowrk starts from 10.0.18.0/16.(Its a Class A network with subnetting of Class B). According to me , no of host i should get with subnet mask of 16 = 655356 but if i go with your calculation my no of host would be 60672.

(256 - 18)* 256 = 60928.

please let me know if i am right or wrong

regards

Neo

Jon Marshall Thu, 04/09/2009 - 11:00

Neo

You do get 65536 ( note not 655356 ).

Not sure why you say my calculation means 256 - 18 ? That's not what i said.

10.0.18.0/16 = network 10.0 which means you have 2 full octets left for hosts

so 256 x 256 = 65536

10.0.18.0 is just a host address in the 10.0.0.0/16 network.

Jon

Jon,

This is not a host address , thats a network id 10.0.18.0/16. If you say broad cast address is 10.0.255.255 , then subtracting 18 from 256 ( third octet) multiplied by 256 will give me less than 65536.

Neo

Jon Marshall Thu, 04/09/2009 - 11:09

Neo

with a /16 ie 255.255 then that is a host address.

ie. 10.0.18.0 255.255.0.0 = 10.0 is the network, everything else is host addresses.

If it was 10.0.18.0/24 then yes that would be a network.

Jon

greg.washburn Thu, 04/09/2009 - 11:04

Wrong ;) The hosts per each /16 subnet/network would be 2^16-2 = 65,536-2 = 65,534.

Jon Marshall Thu, 04/09/2009 - 11:06

Greg

Sorry, yes you are right. I was just trying to emphasize to Neo it shouldn't have been 256 - 18.

Jon