Access to sub network unreachable.

Dave Ihnat dihnat at dminet.com
Sat Jan 10 12:59:21 UTC 2009


Ok, I'm not quite shut up.  I just wanted to mentio that a useful tool
on every Linux/Unix system for doing netmask calculation is 'dc', if you
have trouble doing binary conversions in your head.  Just
set the input or output base to binary, e.g.:

  dc
  2
  o
  248
  p
  11111000

and you have the netmask pattern for 255.255.248.0.  (Well, everyone
knows 255 = 11111111).  The other way:

  dc
  2
  i
  11100000
  p
  224

So you know that a 19-bit netmask would be 255.255.224.0.

(Yeah, there are all SORTS of IP calculators out there--software and
hardware.  But 'dc' is, as I said, ubiquitous ...)

Cheers,
--
	Dave Ihnat
	dihnat at dminet.com




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