Evgeniy Berdnikov via Exim-users wrote:
> On Wed, Dec 30, 2020 at 02:25:19PM +0700, Victor Sudakov via Exim-users wrote:
> > Evgeniy Berdnikov via Exim-users wrote:
> > > Yes, I have. And have you looked at packet time stamps?
> > > IMHO, 3-5 us time interval between SYN-ACK and RST is
> > > too low for userspace responce.
> >
> > Well, the whole story is happening within one hypervisor (bhyve) so
> > network delays can be very low.
>
> It does not matter: any hypervisor should perform a context switch bitween
> kernel process and userspace process, even for container virtulization.
> It's havy task.
>
> > > However, get strace as Jeremy suggested.
> > > I expect ECONNREFUSED on connect().
> >
> > Is this ktrace informative https://termbin.com/zjsv ?
>
> I have never seen such a trace before...
It's FreeBSD's native ktrace. FreeBSD also has dtrace but I have no
experience therewith.
>
> As packet is sent, it may be some problem with TCP_FASTOPEN, probably
> with its handling in hypervisor and/or external firewall.
You must be a wise man Evgeniy! On the exim host, I set sysctl
net.inet.tcp.fastopen.client_enable=0 and the problem seemed to go away.
Now if you care :-) please explain what it was and what I've lost by
disabling fastopen client.
>
> BTW, this trace may be more meaningful with time stamps, turn them on
> if possible.
For its academic value, the same ktrace with Unix timestamps:
https://termbin.com/iemr
--
Victor Sudakov, VAS4-RIPE, VAS47-RIPN
2:5005/49@fidonet
http://vas.tomsk.ru/
