On Fri, Apr 13, 2018 at 10:35 PM, Randy Bush <[email protected]> wrote: > > I believe we've seen bogus low AS number announcements a few times > > before, and they've usually been caused by attemts to configure > > AS path prepending without understanding and/or reading the docs. > > > > Someone might have wrongly assumed that > > > > set as-path prepend 133711 133711 > > > > could be written shorter like > > > > set as-path prepend 133711 2 > > > > and there you go... > > for someone else's prefix? >
Perhaps their policy is something like: "prepend all of transit-provider-1 prefixes by 2, their links are crappy today" followed by output policy: "permit all of my prefixes (matched by as-path-regex) and my customer prefixes (matched by community)" there's probably a bunch of ways this can go sideways, that's just one simple (and seen before) example.
