I thought I saw a tool like this once upon a time, but can't find it anymore...

Anyone know a tool that would take a free range of IP addresses (as in start / end) and calculate a set of submasks that match the given range exactly?

I'm specifically looking for a tool that does not comply to class subnetting. So, for example, given an IP range like: -

The tool should be able to return with two masks to match the exact range:

closed as not constructive by Chris S Feb 13 '13 at 15:39

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  • Not sure about the /32 in your example. See tools.ietf.org/rfc/rfc4632.txt and "Host route". As I read it /32 and /31 are special cases. – Hennes Feb 13 '13 at 13:19
  • Shopping Questions are Off-Topic on any of the Stack Exchange sites. See Q&A is hard, lets go Shopping and the FAQ for more details. – Chris S Feb 13 '13 at 15:39
  • This isn't a shopping question... – dunxd Feb 13 '13 at 16:57
  • @dunxd As it is written ("give me a tool that does X") it's a shopping question - Google is the answer, just ask for subnet calculator. If rewritten to "How do I calculate the optimal subnet mask for X?" the answer would be covered by the canonical IPv4 Subnetting question – voretaq7 Feb 13 '13 at 18:06
  • You mean if rewritten in almost exactly the same way as they phrased the question? I still disagree that this is a shopping question. It isn't asking for product recommendations - it is asking for the right tool to use. Fair enough that this is a dupe, but just closing the question like this chases new users off. – dunxd Feb 14 '13 at 9:44

This web tool works: http://www.ipaddresslocation.org/subnet-mask-calculator.php

See also http://www.subnet-calculator.com/

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