Subject: Re: PMTUD blackhole detection
To: Kevin Lahey <email@example.com>
From: None <firstname.lastname@example.org>
Date: 05/02/2001 09:10:25
>> on PR 12790, I posted a simple patch for TCP PMTUD blackhole detection.
>> if there's no ack for a while, the patch will do the following:
>> - turn off path MTU discovery for IPv4
>> - uses minimum MTU (1280) for IPv6
>> the behavior will remedy path MTU discovery blackhole, if our side
>> is the sender of bigger packet. it does not solve problems when
>> the other side is sending bigger packet and choking with the lack
>> of icmp too big messages.
>> see RFC2923 section 2.1 for the exact description of the issue.
>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...
if you know that PMTUD is failing for particular paths, you should
be able to set a lower path MTU value by using route(8) (use -mtu