[184190] in North American Network Operators' Group

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Re: Question re session hijacking in dual stack environments w/MacOS

daemon@ATHENA.MIT.EDU (Mark Tinka)
Tue Sep 29 03:24:11 2015

X-Original-To: nanog@nanog.org
To: David Hubbard <dhubbard@dino.hostasaurus.com>, nanog@nanog.org
From: Mark Tinka <mark.tinka@seacom.mu>
Date: Tue, 29 Sep 2015 09:23:59 +0200
In-Reply-To: <FCD26398C5EDE746BFC47F43EA52A17305EF20@dino.ad.hostasaurus.com>
Errors-To: nanog-bounces@nanog.org



On 26/Sep/15 16:34, David Hubbard wrote:

>
> Has anyone run into this?  Our users on other platforms don't seem to
> have this issue; linux and MS desktops seem to just use v6 if it's
> available and v4 if not.

I have been tracking down an issue for months where SSH'ing to some
devices (which picks IPv6 by default) from my Mac while in the office
drops the connection, forcing me to reconnect. It's random; sometimes it
happens a lot, sometimes, rarely, other times not at all.

I've sort of suspected OS X to be the issue (10.10.5) here. The
workaround has been to SSH strictly on IPv4 which is always stable. So
it seems to be an issue when the session is carried over IPv6.

This only affects OS X. SSH'ing from FreeBSD, for example, on IPv6 is
stable. To be honest, I've been a little busy to look deeper into this,
but it definitely has something to do with what you describe, I imagine.

Mark.

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