Re: IPv6 checksum errors with divert

From: brian <>
Date: Sat, 30 Oct 2021 23:50:34 UTC
Maybe with a tcpdump or packet capture search for http error codes; has a list. 400 
errors are what usually lead to errors clients observe while the server 
is still alive.


On 10/30/2021 4:33 PM, Peter wrote:
> Hi Andrey, hi all,
>    there is at least one further issue with divert (and dummynet)
> and IPv6:
> If I put EITHER a divert OR a dummynet pipe/queue into the OUTgoing
> (layer3) ruleset to the uplink interface, then Youtube is not able to
> insert their advertisments into playback, and may hang entirly on
> playback.
> That seems to not happen due to timing or bandwith issues, but due to
> the sheer existance of a dummynet (or divert). And if I move the
> dummynet to the incoming, INTRAnet-facing side of the router, the
> problem does not appear.
> So there must still be some other bit in the IPv6 (or in the mbuf?)
> that gets improperly mangled during divert and also during dummynet.
> It appears a bit difficult to hunt that one down, due to the sheer
> amount of traffic involved in YT streaming, and also since I do not
> know exactly for what to look...
> Any helpful ideas are welcome.
> Cheerio,
> PMc