Bug#1011756: cloud.debian.org: Vagrant debian/testing64: sshd rejects default insecure ssh-rsa key, hangs waiting for SSH

[Emmanuel Kasper <manu@debian.org>]

Thanks Andrew for the time you took investigating this.

So I understood right, this was a problem in the way Vagrant ruby
library did ssh connection, as in presence of a ssh-rsa key it would
always try to connect using a SHA-1 signature algorithm (the algo which
was dropped by newer OpenSSH) instead of trying SHA-256 or SHA-512 (see
https://github.com/hashicorp/vagrant/issues/11783#issuecomment-818951984)

This means this was actually a bug in Vagrant, not in the boxes
themselves. This is proved by your fact that the testing version of
Vagrant can perfectly connect to the testing boxes.

Not sure what to here, I am thinking of reassigning this bug report to
the vagrant package, and maybe point the FAQ to this bug report.