Re: Level 3 BGP Advertisements

[Matt Addison <matt.addison () lists evilgeni us>]

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.