With Ubuntu 15.10 and before, I had a host entry with "Protocol 1" in my .ssh/config file.
Ubuntu 16.04 doesn't have support for SSH1 anymore per default.
corben@ubuntu1604:~$ ssh -1 host
ssh1 is not supported
When using the ssh client with any host entry having a "Protocol 1" line in .ssh/config it complains with:
corben@ubuntu1604:~$ ssh host
.ssh/config line <nr>: Bad protocol spec '1'.
To connect to my host using ssh1, I could install the package openssh-client-ssh1 and call ssh1 instead of ssh .
But the ssh1 client doesn't use the host entry configured in .ssh/config, when the "Protocol 1" line is omitted.
There is no man page for ssh1 and "man ssh" still lists the -1 option for protocol version 1. I want to use a host entry as I have port forwarding and ssh keys configured, which I don't want to enter each time on the command line.
How to use ssh and ssh1 in coexistence and .ssh/config?
The host is an embedded device still in service, where no firmware updates will be released. As it is used in a LAN environment the security aspect using ssh version 1 isn't an issue.
Best Answer
Protocol SSH1 is gone for good and it is time to accept that. It will get removed from manual pages and documentation very soon so it will not confuse users. It is pretty unclear what you are trying to do.
ssh1should still read the~/.ssh/config, if Ubuntu maintainers didn't break something. Can you post the verbose log (ssh1 -vvv host1) from your connection to your ssh1 host? Does usingssh1 -1 host1change something?