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I'm a bit confused by the logic behind this.

How would I find the IP address given just the subnet mask and network address?

I know that given the IP address and subnet mask, I can obtain the network address by converting to decimal dot notation of both addresses to binary and using the AND bitwise operation.

I must just not be seeing something so obvious.

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There is no way to determine a single host's IP address from the network address and mask. The network address and mask will give you the range of possible host addresses, but not any individual host's IP address.

As you wrote, it is possible to derive the network address from the host address and mask, but it is not possible to do the reverse since you can go from specific to range, but a range has nothing in it to give you a specific.

It's like trying to know which finger is represented by "fingers". You can know that "the left index finger" is is in "fingers on the left hand", but knowing "fingers on the left hand" doesn't give you the specific finger.

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  • Ah! Thanks for the reply! So i can get a range of of hosts on that particular subnet. Can i obtain DNS names assigned for those hosts just given the Subnet Mask and Net address? – JimHalpert Nov 11 '15 at 23:44
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    DNS is an application layer protocol. IP knows nothing about DNS or names. – Ron Maupin Nov 11 '15 at 23:46
  • I see. Thanks! If i could upvote I would. – JimHalpert Nov 11 '15 at 23:49

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