Level 3 BGP Advertisements

Grzegorz Janoszka Grzegorz at Janoszka.pl
Wed Aug 29 16:06:12 CDT 2012

On 29-08-12 22:55, STARNES, CURTIS wrote:
> 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, 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.

Yes, actually there are people over Internet blocking all IP's ending
with 0 or 255 as a kind of bogon or other old wives' tale.

Grzegorz Janoszka

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