Mailinglist Archive: opensuse-edu (132 mails)

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Re: [suse-linux-uk-schools] Some showstopping network issues..
  • From: "Mark Evans" <mpe@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
  • Date: Wed, 26 Jun 2002 15:00:20 +0000 (UTC)
  • Message-id: <20020626141408.25799.qmail@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> And yes we run just one internal subnet of
> 255.255.252.0, with the broadband on the foreign
> x.x.254.0 subnet. Interesting to note that linux
> counts x.x.253.0 as an invalid subnet with the foreign

That's because it is invalid, valid subnet masks
are
128.0.0.0, 192.0.0.0, 224.0.0.0, 240.0.0.0, 248.0.0.0,
252.0.0.0, 254.0.0.0, 255.0.0.0, 255.128.0.0,
255.192.0.0 255.224.0.0, 255.240.0.0, 255.248.0.0,
255.252.0.0, 255.254.0.0, 255.255.0.0, 255.255.128.0,
255.255.192.0, 255.255.224.0, 255.255.240.0,
255.255.248.0, 255.255.252.0, 255.255.254.0,
255.255.255.0, 255.255.255.128.0. 255.255.255.192,
255.255.255.224, 255.255.255.240, 255.255.255.248,
255.255.255.252, 255.255.255.254

With 0.0.0.0 and 255.255.255.255 having special
meanings.

An alternative way of indicating subnet masks is
simply the number of 1's on the LHS of the 32
bit number.

With 1 being 128.0.0.0 and 31 being 255.255.255.254.

255.255.252.0 is 22 and 255.255.254.0 is 23
The first gives you 1022 usable IP addresses,
the second 510.

> subnet, even tho NT is fine with it - 254 is fine on
> the test comp btw.

That's NT for you.

--
Mark Evans
St. Peter's CofE High School
Phone: +44 1392 204764 X109
Fax: +44 1392 204763

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