[157442] in North American Network Operators' Group
Re: Issues encountered with assigning .0 and .255 as usable addresses?
daemon@ATHENA.MIT.EDU (Job Snijders)
Mon Oct 22 18:20:41 2012
From: Job Snijders <job@instituut.net>
In-Reply-To: <73A9A2579638014A8254BF9FE31DDB244FAF4FA6@mbx2.jiveland.com>
Date: Mon, 22 Oct 2012 17:20:13 -0500
To: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Hi Paul,
On Oct 22, 2012, at 5:07 PM, Paul Zugnoni =
<paul.zugnoni@jivesoftware.com> wrote:
> Curious whether it's commonplace to find systems that automatically =
regard .0 and .255 IP addresses (ipv4) as src/dst in packets as traffic =
that should be considered invalid. When you have a pool of assignable =
addresses, you should expect to see x.x.x.0 and x.x.x.255 in passing =
traffic (ie. VIP or NAT pool, or subnets larger than /24). Yet I've run =
into a commercial IP mgmt product and getting reports of M$ ISA proxy =
that is specifically blocking traffic for an IP ending in .0 or .255.
>=20
> Any experience or recommendations? Besides replace the ISA proxy=85. =
Since it's not mine to replace. Also curious whether there's an RFC =
recommending against the use of .0 or .255 addresses for this reason.
In the post-classfull routing world .0 and .255 should be normal IP =
addresses. CIDR was only recently defined (somewhere in 1993) so I =
understand it might take companies some time to adjust to this novel =
situation. Ok, enough snarkyness!
Quite recently a participant of the NLNOG RING had a problem related to =
an .255 IP address. You can read more about it here: =
https://ring.nlnog.net/news/2012/10/ring-success-the-ipv4-255-problem/ =
So yes, apparently problems like these still arise once in a while. My =
recommendation would be to fix the equipment and not blame it on .0 or =
.255.=20
Kind regards,
Job Snijders=
