IP and Subnet
>I'm given a Subnet mask of 255.255.240.0
It dosn't have a network class. The old class A/B/C sytem was
replaced by CIDR (classless inter domain routing) years ago though
lot of people continue to repeat out of date information.
255.255.240.0 is a /20 network block.
>I have to identify the network class, subnet and the node for the
>IP address 142.56.130.78.
The block of ip addreses containing 142.56.130.78/20 is
142.56.128.0 to 142.56.143.255
I'm not sure what you mean by node. To me a node is an individual
machine so the node is the machine which has that ip address.
>I know its class B.
It is not a class B. A class B block of ip addresses has a subnet mask
of 255.255.0.0
>for class B We have:
>net: 255.xxx.xxx.xxx
Completly wrong. That is an old class A block, now called a /8
>subnet: xxx.255.xxx.xxx
That is not a valid subnet mask.
Added after 15 minutes:
Incidentally that ip address is part of a class B allocation however the network administrator can divide the ip space into smaller blocks as he sees fit for different LAN's/buildings/offices.
OrgName: Alberta Energy Company Limited
Address: 1800, 855-2nd Street S.W.
City: Calgary
NetRange: 142.56.0.0 - 142.56.255.255
CIDR: 142.56.0.0/16
NetName: AECNET
NetHandle: NET-142-56-0-0-1
Parent: NET-142-0-0-0-0