[155895] in North American Network Operators' Group
Re: Level 3 BGP Advertisements
daemon@ATHENA.MIT.EDU (james machado)
Wed Aug 29 18:31:14 2012
In-Reply-To: <A5FACB06A6163C4790FAE19E1C9314D7013A4D4EE32C@MAILSRV.granbury.k12.tx.us>
Date: Wed, 29 Aug 2012 15:30:22 -0700
From: james machado <hvgeekwtrvl@gmail.com>
To: "STARNES, CURTIS" <Curtis.Starnes@granburyisd.org>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Wed, Aug 29, 2012 at 1:55 PM, STARNES, CURTIS
<Curtis.Starnes@granburyisd.org> wrote:
> Sorry for the top post...
>
> Not necessarily a Level 3 problem but;
>
> We are announcing our /19 network as one block via BGP through AT&T, not broken up into smaller announcements.
> Earlier in the year I started receiving complaints that some of our client systems were having problems connecting to different web sites.
> After much troubleshooting I noticed that in every instance the xlate in our Cisco ASA for the client's IP last octet was either a 0 or 255.
> Since I am announcing our network as a /19, the subnet mask is 255.255.224.0, that would make our network address x.x.192.0 and the broadcast x.x.223.255.
> So somewhere the /24 boundary addresses were being dropped.
>
> Just curious if anyone else has seen this before.
some OS's by M and others as well as some devices have IP stacks which
will not send or receive unicast packets ending in 0 or 255. have had
casses where someone was doing subnets that included those in the DCHP
scopes and the computers that received these addresses were black
holes.
james
