On Tue, Feb 22, 2011 at 4:55 PM, Jack Carrozzo <jack@crepinc.com> wrote:
Maybe I read your question wrong, but null-routing things at your border is often not very useful if the traffic is flooding your transit links. Most transits publish their community lists - you just need to tag the prefix you want to blackhole with the right community.
This is certainly true. Although most "big transit networks" offer this feature today, there are some important differences in what some of them will and won't accept. Some will only learn /32s, some say they'll accept /30-/32 but nothing shorter, some will honor anything you send them. This may be undocumented. Some networks seem to have forgotten about this feature when implementing IPv6, even though it is offered for IPv4. I don't see any value in not accepting a RTBH /24 but accepting a /30. I also don't know of any platform issues which would make deploying RTBH for IPv6 BGP customers any more difficult than doing so for IPv4. -- Jeff S Wheeler <jsw@inconcepts.biz> Sr Network Operator / Innovative Network Concepts