prefix filtering per IRR - practices
Hi, I have a question regarding what's the most common practice [1] for transit ASs to filter prefixes from their BGP customers when using IRR data. (which of course everyone does...) Would many/most/all/none : a) accept only the prefixes listed in route objects or b) accept these and anything "upto /24" (or "le 24") I was hoping / assuming the latter but I start getting a different impression. Yep, and apart from the current status, the tendency would be of interest. Thanks, Frank [1] after "my network, my rules"
From my experience, networks that are capable of filtering from IRR objects generally filter for exact routes, meaning no "le 24". While I've always found networks to be set in their ways, I know some people that have managed to get their filters changed to allow longer prefixes without needing additional objects.
But ultimately, it does help prevent the leaking of internal routes. -Chris On Fri, Nov 22, 2013 at 6:55 AM, Frank Habicht <geier@geier.ne.tz> wrote:
Hi,
I have a question regarding what's the most common practice [1] for transit ASs to filter prefixes from their BGP customers when using IRR data. (which of course everyone does...)
Would many/most/all/none : a) accept only the prefixes listed in route objects or b) accept these and anything "upto /24" (or "le 24")
I was hoping / assuming the latter but I start getting a different impression. Yep, and apart from the current status, the tendency would be of interest.
Thanks, Frank
[1] after "my network, my rules"
Le 22/11/2013 17:57, Chris Rogers a écrit :
From my experience, networks that are capable of filtering from IRR objects generally filter for exact routes, meaning no "le 24".
Hi, Are you sure? My experience is, with a small number of exceptions, that "le 24" ('route' or 'route-set,' sometimes in relation with "is in AS-set of peer") is an often used policy. Maybe it depends on what kind of networks one's looking at? Cheers, mh
While I've always found networks to be set in their ways, I know some people that have managed to get their filters changed to allow longer prefixes without needing additional objects.
But ultimately, it does help prevent the leaking of internal routes.
-Chris
On Fri, Nov 22, 2013 at 6:55 AM, Frank Habicht <geier@geier.ne.tz> wrote:
Hi,
I have a question regarding what's the most common practice [1] for transit ASs to filter prefixes from their BGP customers when using IRR data. (which of course everyone does...)
Would many/most/all/none : a) accept only the prefixes listed in route objects or b) accept these and anything "upto /24" (or "le 24")
I was hoping / assuming the latter but I start getting a different impression. Yep, and apart from the current status, the tendency would be of interest.
Thanks, Frank
[1] after "my network, my rules"
participants (3)
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Chris Rogers
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Frank Habicht
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Michael Hallgren