OpenSSH Always Hangs When Connecting to Remote

Eitan Adler lists at
Mon Sep 21 05:48:44 AEST 2015

On 20 September 2015 at 11:28, Carlo Abelli <carlo.abelli at> wrote:
> On 09/20/2015 03:25 AM, Darren Tucker wrote:
>> I suspect a path mtu problem.  The key exchange packet is one of the
>> first large ones in an SSH connection so it tends to show up such problems.
>> See
>> <>
> Has this been changed? SSH used to work fine on my old machine. My local
> mtu and server mtu are higher than required. Therefore the only thing I
> could expect would be a lower mtu on the vpn. Has this changed in recent
> versions. As previously I was using OSX I expect the OpenSSH version was
> older. Still strange to me that it worked before and not now. I will
> test tomorrow to see if connecting on the actual network solves the issue.

It is common for VPNs to introduce lower MTU limits and to not
correctly send ICMP code 3 type 4 packets.  This isn't so much of an
SSH problem as it is a misconfiguration on the network path to the
destination.  See for further

Eitan Adler

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