I've been troubleshooting an issue with Vagrant,
$ vagrant ssh
OpenSSL version mismatch. Built against 100020ef, you have 1000106f
$
but if I build the corresponding ssh command manually with the parameters provided by vagrant ssh-config
this succeeds (alternatively these are provided if I do vagrant ssh --debug
: the final line before it attempts connection contains all the parameters it uses). What makes it even more puzzling is that the versions of openssh and OpenSSL match on the Virtualbox host and client machines (don't be thrown by the 1.0.2n and 1.1.1 differing between ssh and OpenSSL results, it turns out these do play together OK) - the point is that the commands below give the same results on the host and the client,
$ ssh -V
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n 7 Dec 2017
$ openssl version
OpenSSL 1.1.1 11 Sep 2018
This is on a Mint 19.3 - so Ubuntu 18.04-based system.
In fact I did find the answer so it's posted below to hopefully help you avoid wasting too much time tracking down any similar issue.