Groups > comp.os.linux.networking > #1600

Dealing with a network knowledge troll!

Newsgroups	comp.os.linux.networking
From	Mike Lovell <dev.null@b0h0.com>
Subject	Dealing with a network knowledge troll!
Organization	home.b0h0.com
Message-ID	<slrnk3drvp.1eu.dev.null@usenet.home.b0h0.com> (permalink)
Date	2012-08-23 22:07 -0500

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Hello,

I've got a guy who claims these:

	10.255.255.81/24
	192.168.255.81/24

Are invalid unicast IP's, because any IP with a "255" in it *anywhere*
is reserved for being a broadcast IP.

To which he cites:
http://www.comptechdoc.org/independent/networking/guide/netaddressing.html


Now I immediately know this is wrong because you can use a "0" or "255"
on the end of a host IP:
http://en.wikipedia.org/wiki/IPv4#Addresses_ending_in_0_or_255


And of course the RFC says it's fine to use a "255" in the 1st to 3rd
octets.  Nothing about this is reserved or makes the address
specifically a broadcast one.


And you can even find reachable hosts out there with "255" in them:


host ns2.televork.ee
ns2.televork.ee has address 81.21.255.1

host www.lepton-line.jp
www.lepton-line.jp has address 121.83.255.1


So every router between me and them (for me to reach them) would have to
be broken it allow this, if the other guy is right about them being
invalid!



Question:

Am I correct (the IP's are valid) or is he (the IP's are invalid)?  And why?

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Thread

Dealing with a network knowledge troll! Mike Lovell <dev.null@b0h0.com> - 2012-08-23 22:07 -0500
  Re: Dealing with a network knowledge troll! David Brown <david@westcontrol.removethisbit.com> - 2012-08-24 09:05 +0200
  Re: Dealing with a network knowledge troll! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-08-24 07:17 +0000
    Re: Dealing with a network knowledge troll! Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2012-08-24 10:29 -0500
    Re: Dealing with a network knowledge troll! Mike Lovell <dev.null@b0h0.com> - 2012-08-24 10:53 -0500
      Re: Dealing with a network knowledge troll! "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2012-08-24 14:02 -0400
      Re: Dealing with a network knowledge troll! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-08-24 20:21 +0000
  Re: Dealing with a network knowledge troll! Richard Kettlewell <rjk@greenend.org.uk> - 2012-08-24 09:07 +0100
  Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-24 12:09 -0500
    Re: Dealing with a network knowledge troll! Moe Trin <ibuprofin@painkiller.example.tld.invalid> - 2012-08-24 14:29 -0500
      Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-24 15:58 -0500
        Re: Dealing with a network knowledge troll! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-08-24 22:23 +0000
          Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-25 12:40 -0500
    Re: Dealing with a network knowledge troll! Richard Kettlewell <rjk@greenend.org.uk> - 2012-08-25 09:38 +0100
      Re: Dealing with a network knowledge troll! telsar <noone@nowhere.com> - 2012-08-25 12:35 -0500

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