-----BEGIN PGP SIGNED MESSAGE----- Please note that the changes to Sprintlink's filtering policies that Marc Hidalgo and I announced at NANOG have been implemented, and should be visible as BGP sessions with our external peers (MCI, ANS, Alternet, PSI et al.) reset over time. It is hoped that the changes won't be flawed, but any oddities would be nice to know about. The two and a half week delay in implementation is my own fault. Note that the policy is now: [allow none of the RFC 1597 et succ. reserved addresses] in 0/8-126/8, allow no subnets of historical As that were not announced in July 1995[*] 127/8-191/8, allow nothing longer than /16 [*] 192/8-205/8, allow nothing longer than /24 206/8-223/8, allow nothing longer than /19 195/8 [RIPE block, 12 dec 95], allow nothing longer than /19 [other RIPE and APNIC blocks that have begun being allocated from since July 1995 will also be filtered on the /19 boundary] The principal change is that we used to disallow /19s in 207/8-223/8 and 195/8, and this was not in line with the minimal allocation units performed by the three primary registries. Please also note that we have also already accumulated a couple of months of successful experience with differential filtering, and will be both tightening up the filtering in the newly unfiltered space and tweaking the currently-used values up and down. Very roughly speaking, the goal is that if you have a very long prefix (like a /24), and it flaps a couple times, you can go home for the day. If you do even the slightest bit of aggregation (into a /23, for example), then you are much less likely to be dampened in the face of minor flapping, and you will be dampened for less time. Once you have aggregated enough addresses to comprise a /18 or shorter prefix, you will be dampened with values very much in line with the default you get from Cisco's "bgp dampening" command. At the moment, you are much more likely to be dampened if you are NOT a Sprint customer. That is, the normal values for "bgp dampening" are in place if you have a customer connection to SprintLink or ICM. However we will be evaluating the engineering and operational effects that a similar policy with respect to SprintLink customers, as an effort to encourage some of our lazier customers to begin doing their own aggregation wherever possible. You may not be surprised that the success of this differential dampening experimentation has played a large role in the easing-up of our filtering policies. Sean. -----BEGIN PGP SIGNATURE----- Version: 2.6.2 Comment: PGP Public Key in ftp://ftp.sprintlink.net/engineer/smd/pgpkey iQCVAwUBMcmkVkSWYarrFs6xAQEblQQAg60neKgLSGpQZ2e0n67MRjVNd+eLDSaJ Ceea+2bypM8V9QD6nTr6zEJ302qLrIK6b9e0lLmgFPpoUs1Rb3KDqv4ruAQKmkBo dDu5NxIAlG9b+qvXTuocPA81y4+zWKMOaFHCPFNksMIzhA19pRYLndiuJqRifiHn CQyAZGorrwQ= =uyTH -----END PGP SIGNATURE-----