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Re: Level 3 BGP Advertisements
From: Matt Addison <matt.addison () lists evilgeni us>
Date: Wed, 29 Aug 2012 19:08:13 -0400

Sent from my mobile device, so please excuse any horrible misspellings.

On Aug 29, 2012, at 18:30, james machado <hvgeekwtrvl () gmail com> wrote:

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

MSKB 281579 affects XP home and below. Good times anytime someone adds
a .0 or .255 into an IP pool.


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