[OmniOS-discuss] strangeness ssh into omnios from oi_151a9

[Lauri Tirkkonen]

On Mon, Sep 28 2015 16:20:03 +0200, Richard PALO wrote:
> Le 28/09/15 15:46, Lauri Tirkkonen a écrit :
> > On Mon, Sep 28 2015 08:21:46 -0400, Dan McDonald wrote:
> >>
> >>> On Sep 28, 2015, at 8:15 AM, Dan McDonald <danmcd at omniti.com> wrote:
> >>>
> >>> If 5850 is indeed the problem, you need to report this to the
> >>> illumos developers list, including a deterministic way of
> >>> reproducing it.
> >>
> >> I see you filed bug 6264, which is a good first step.  Please make
> >> sure you summarize the how-to-reproduce in it.
> >>
> >> I also wonder if you patch your oi_151a9 box with 5850, AND keep 5850
> >> on your OmniOS machine, whether or not this problem ALSO goes away.
> >> After all, this fix specifically targets machines that drop
> >> timestamps...
> > 
> > If my analysis is correct (see the mail I sent to this thread
> > previously), then applying 5850 to the oi_151a9 box will cause the issue
> > to disappear -- both peers will then ignore the injected window change
> > segment because it has no timestamps. Of course, it's possible that the
> > middlebox won't like being ignored and might cause other failures (it
> > could still inject RSTs, for example, since those are not required to
> > have timestamps).
> > 
> 
> If I experienced the issue, chances a great anybody else with oi_151a9 have it
> as well in France as the OI machine is connected to an Orange (previously known
> as France Télécom) Business Services SDSL router and the Omnios box to a Freebox (Free Télécom).

It just occurred to me that if timestamp options don't get negotiated at
all on the connection, both peers should be fine with this injection and
continue to function. So as a workaround you could try disabling
timestamps on the oi_151a9 box. I see the following ndd options:

    % ndd -get tcp ?|grep tstamp       
    tcp_tstamp_always              (read and write)
    tcp_tstamp_if_wscale           (read and write)

You could try setting those to 0 and see if that works around the hang
(untested, so beware). This obviously turns off TCP timestamps, but how
useful are they on the pre-5850 box anyway if your middlebox has been
defeating their use all this time? :)

-- 
Lauri Tirkkonen | lotheac @ IRCnet