From: Brian Candler <B.Candler@...>
Date: 2003-07-02T01:12:15+09:00
Subject: IP arithmetic

Are there any functions in the Ruby standard library which convert
dotted-decimal IP addresses to numeric form, *without* doing any forward or
reverse DNS lookups?

I want to do some address subnet matching: e.g.

    if ip_match("1.2.3.4", "1.2.3.0/24")
      ... etc
    end

and the efficient way of doing this would be to do bitwise operations on the
numeric form.

Cheers,

Brian.