>>>>> "itojun" == itojun  <itojun@iijlab.net> writes:
    >> Cool.  Is there some way that we could set a flag in the route, rather
    >> than just having a per-connection flag?  That way we only have to pay
    >> the cost of the two timeouts once per black hole, rather than once per
    >> connection...

    itojun> if you know that PMTUD is failing for particular paths, you
    itojun> should be able to set a lower path MTU value by using route(8)
    itojun> (use -mtu keyword).

  This doesn't work for, e.g. web servers with random connects from all
over. Having received one connection from a client, the odds of a getting a
second one is high, and there may in fact be 4+ concurrent ones already.