Comment 0 for bug 1670745

When I use the port option with ssh-keygen, the result is not compatible with ssh known_host file format.

UBUNTU VERSION :
================
lsb_release -rd
Description: Ubuntu 16.04.1 LTS
Release: 16.04

BAD :
============
:~/.ssh$ cat /etc/issue
Ubuntu 16.04.1 LTS \n \l
:~/.ssh$ ssh-keyscan -v -p [...port...] -t ecdsa -H [...snip...]
debug1: match: OpenSSH_6.7p1 Debian-5+deb8u3 pat OpenSSH* compat 0x04000000
# [...snip...]:[...port...] SSH-2.0-OpenSSH_6.7p1 Debian-5+deb8u3
debug1: Enabling compatibility mode for protocol 2.0
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: <email address hidden>
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: <email address hidden> MAC: <implicit> compression: none
debug1: kex: client->server cipher: <email address hidden> MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
[|1|BEEwVcggbNPf7fUydgU4O+BDoLg=|9SmWBUxFZkpR70Hqq8uqxLAzXFU=]:[...port...] ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBLEde+dZfL0TW6Z9jh+gOkW5fG/qeP9JAejKQXdmg9D7CH4NwMrWDEjXBDDo6iirIPAB6M0uUnK2mDw7uUWXYt8=

==> we see the port number because it is not hashed !

GOOD :
============
rm ~/.ssh/known_hosts
:~/$ ssh -p [...port...] [...snip...]
The authenticity of host '[[...snip...]]:[...port...] ([[...snip...]]:[...port...])' can't be established.
ECDSA key fingerprint is SHA256:b/Jx+y3fNWFqOqTzFRI3XGrz33DBtAFFLmQaYQYFRnM.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[[...snip...]]:[...port...],[[...snip...]]:[...port...]' (ECDSA) to the list of known hosts.
[...snip...]@[...snip...]'s password:

:~/$ !cat
cat ~/.ssh/known_hosts
|1|qdg91H9/DMHLO7yGOivI17+WFQI=|B+a6SrzF1GBd3XFvmAvQRnJxLWs= ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBLEde+dZfL0TW6Z9jh+gOkW5fG/qeP9JAejKQXdmg9D7CH4NwMrWDEjXBDDo6iirIPAB6M0uUnK2mDw7uUWXYt8=
|1|8I/vbrBV04VaUF12JXRwxvAL9So=|ToMf+kRwbSeNertVdUVuG3iLdH8= ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBLEde+dZfL0TW6Z9jh+gOkW5fG/qeP9JAejKQXdmg9D7CH4NwMrWDEjXBDDo6iirIPAB6M0uUnK2mDw7uUWXYt8=

==> we cannot see the port number as it is well hashed !

REMARKS :
==============
Same problem has already reported here (on macOS): https://github.com/ansible/ansible-modules-extras/issues/2651

It seems that ssh-keyscan version and open-ssh version differs :
dpkg -l | grep openssh :: ii openssh-client 1:7.2p2-4ubuntu2.1 [...]
ssh-keyscan -v [...] :: debug1: match: OpenSSH_6.7p1 Debian-5+deb8u3 pat OpenSSH* compat 0x04000000

It is very annoying because I am trying to manage hand installed VMs with Ansible. For that I want to automate SSH host keys storing in known_hosts database. And because of this bug I can't. (ansible KIKIN project in development).

Thank you,
BR,
Gautier HUSSON.