Disable SSHAgent with command line option

Question

How can I tell ssh with a command line option to not use the SSH-Agent?

ssh -a does something different. It does not forward the agent, but uses it.

I read the man page, and could not find a solution.

Unsetting SSH_AUTH_SOCK would work, but a command line option would be much better in my context.

Answer 1

You can force ssh to use anything else than a SSH key to authenticate (e.g. password) with

ssh -o PubkeyAuthentication=no ...

this way of course the agent will be ineffective. If you want to use a key, you can also specify it explicitly and ssh will only use that key and not all that are in the agent:

ssh -i path/to/id_rsa -o IdentitiesOnly=yes -F /dev/null ...

You mentioned SSH_AUTH_SOCK. You can unset it just in the context of your ssh command like this:

SSH_AUTH_SOCK= ssh ...

Note the space after SSH_AUTH_SOCK=. This way your are sure that the agent is not used while at the same time not modifying your working environment.

Answer 2

I know this is an old question, but the correct answer to "How can I tell ssh with a command line option to not use the SSH-Agent?" hasn't been given yet:

• use the -o IdentityAgent=none option

From https://man7.org/linux/man-pages/man5/ssh_config.5.html (emphasis added):

IdentityAgent

Specifies the UNIX-domain socket used to communicate with the authentication agent.

This option overrides the SSH_AUTH_SOCK environment variable and can be used to select a specific agent. Setting the socket name to none disables the use of an authentication agent. ...