On Sun, Jun 15, 2008 at 11:12:25AM -0300, Rubens Kuhl Jr. wrote: > 1) I've seen this behavior before; you are not alone in the universe.
Thank $DEITY for that. <grin> > 2) Most likely there is a balanced channel on the path, either L3 or > L2, and one of the links in the bundle is dead but has not been > detected as such. A multiple-link bundle which is load balanced by source/destination pair with an undetected dud link? I hadn't thought of that, but it does make an *awful* lot of sense. (Although, not being a big-network transit kinda person, I don't know if such a thing actually exists <grin>) I'll mention it (or ask about it) as a possibility next time I talk to the relevant people, though. Thanks, - Matt > On Sun, Jun 15, 2008 at 11:01 AM, Matt Palmer <[EMAIL PROTECTED]> wrote: > > We're seeing some really weird issues with connections that go through / to > > Level3 IP space. Basically, certain "pairs" of IPs (particular L3 IPs > > coupled with particular IPs of ours) have dodgy/nonexistent connectivity, > > but if you change the IP at either end everything's hunky dory. > > > > I've sniffed (from both ends) pings going from a host in L3 space to our end > > and seen the pings arrive at our end and head back in the direction of L3, > > but they never get to their destination. Traceroutes from L3 stop at the > > next-to-last hop, while traceroutes back get to the hop before L3 space and > > stop. > > > > All of this behaviour is source/dest *pair* specific -- if I ping/traceroute > > from another address (in the same netblock as the problematic IP, so all the > > same equipment is involved) at either end, or to another address (again, > > same netblock) at either end, it all works again. > > > > I've got two questions: > > > > 1) Has anyone else seen similar behaviour from L3 (or other providers, > > even), so I know I'm not going mad? > > > > 2) What sort of configuration problem or software bug would cause this sort > > of problem to occur? If it was an IP blacklist (or even a block routing > > issue) anywhere along the line, surely it wouldn't be sensitive to > > changing the other end's address to another one in the same /24? > > > > Any insight/anecdotes/etc would be greatly appreciated, as it's starting to > > do my head in. Just knowing I'm not alone with this insanity would be nice > > at this point. <grin> > > > > If it makes any difference, the blocks I'm working from at my end are > > Internap, in 74.201.254.0/23 (we don't have all of it, just most of it), > > while the far end is 8.12.35.0/24.
