There are lots of transits that will take le 32 on their customers inbound but filter le 24 on egress announcements. On Fri, Oct 2, 2015 at 12:47 PM, Jason Baugher <jason@thebaughers.com> wrote:
Are you suggesting that the Tier 1 and 2's that I connect to are not filtering out anything shorter than /24? My expectation is that they are dropping shorter than /24, just like I am.
Correct me if I'm wrong, but every *NOG BGP best practices document I've read has advocated dropping all prefixes shorter than /24 at ingress and egress.
On Fri, Oct 2, 2015 at 11:34 AM, William Herrin <bill@herrin.us> wrote:
On Fri, Oct 2, 2015 at 11:55 AM, Suresh Ramasubramanian <ops.lists@gmail.com> wrote:
Besides which more than one provider filters by a minimum prefix length per /8 - wasn't Swisscom or someone similar doing that? So multi homing with even a /24 is somewhat patchy in terms of effectiveness
Hi Suresh,
That hasn't been true for something like a decade. Anybody who filters anything shorter than /24 without also taking a default route (or the equivalent) is not fully connected to the Internet.
Regards, Bill Herrin
-- William Herrin ................ herrin@dirtside.com bill@herrin.us Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>
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