ssh-add complains: Could not open a connection to your authentication agent

Question

I've been trying to get ssh-add working on a RaspberryPi running Raspbian.

I can start ssh-agent, when I do it gives the following output into the terminal:

SSH_AUTH_SOCK=/tmp/ssh-06TcpPflMg58/agent.2806; export SSH_AUTH_SOCK;
SSH_AGENT_PID=2807; export SSH_AGENT_PID;
echo Agent pid 2807;

If I run ps aux | grep ssh I can see it is running.

Then I try to run ssh-add in order to add my key passphrase, and I get the following:

Could not open a connection to your authentication agent.

Any ideas?

Solution 1

Your shell is meant to evaluate that shell code output by ssh-agent. Run this instead:

eval "$(ssh-agent)"

Or if you've started ssh-agent already, copy paste it to your shell prompt (assuming you're running a Bourne-like shell).

ssh commands need to know how to talk to the ssh-agent, they know that from the SSH_AUTH_SOCK environment variable.

Solution 2

Try this one:

$ ssh-agent /bin/sh
$ ssh-add $yourkey

Solution 3

This question has been also very well covered on Stackoverflow.

eval `ssh-agent -s`

ssh-add

Solution 4

If using csh as a shell (FreeBSD PI) this could work:

eval `ssh-agent -c`

next you only need to do something like:

ssh-add ~/.ssh/id_rsa

Solution 5

You may also use the following syntax:

ssh-agent sh -c 'ssh-add && echo Do some stuff here.'

View more solutions

Comments

[sunnysideup]

Try eval $(ssh-agent)

[geek_guy]

Thanks, I didn't quite understand how it works. Thats very muchly appreciated.

[RaduM]

Or you can enter ssh-agent bash and after the ssh-add will work

[Denys S.]

@Stephane, do I get it correctly that ssh-agent command just prints the output of it's execution while eval version actually runs the command?

[Stéphane Chazelas]

@DenysS. Well no, it does its setup and then tells your shell how to update its environment to be able to contact it. It cannot do that by itself. It can start a new shell with the updated environment (that's what ssh-agent bash does), but it cannot update the memory of a separate process running a foreign command (your already running shell).

[Denys S.]

@StephaneChazelas, if my ssh-agent is started on boot but I still have to eval it in my shell does it mean that it is not automatically evaluated for every shell and has to be configured somehow by the root user?

[Joseph Snow]

This actually worked for me where none of the other answers worked.

[Ain Tohvri]

This isn't working for me, if you go ssh-agent sh -c "ssh-add -l" it will tell you you have no identities.

[kenorb]

Because you've to add it first, for example: ssh-agent sh -c "ssh-add && ssh-add -l" will print your identity.

[Stéphane Chazelas]

@KamijouTouma, I've reverted the edit. Please add that information in your own answer as I don't agree with all you've said in that edit.

[Stéphane Chazelas]

Note that you can also give root access to your ssh-agent by doing sudo SSH_AUTH_SOCK="$SSH_AUTH_SOCK" npm install...

[Belldandu]

Tried both also bash is bourne again shell and neither worked properly. all users on my debian jessie instance including root are set to use bash by default.

[Stéphane Chazelas]

You forgot the quotes around `...`. Without them, the split+glob operator is invoked on the output.

[Belldandu]

i tried eval "$(ssh-agent)" ill be looking later to see if there is some sort of configuration error. Although the current way i have given this guide allows free control over which user you wish to be since your already root and can access any users id_rsa thats on the server. So once i get it working appropriately ill edit my answer.

[Belldandu]

@StéphaneChazelas is this acceptable?

[slackmart]

If you are using the fishshell, this answer works. ssh-agent /usr/bin/fish.

[IgorGanapolsky]

I get an error: "Could not open a connection to your authentication agent."

[IgorGanapolsky]

I get an error: "Could not open a connection to your authentication agent."

[IgorGanapolsky]

"bash: start-ssh-agent: command not found"

[IgorGanapolsky]

I still get an error: key_load_private_type: Permission denied

[cjm]

@slackmart If you installed fish in BSD, its location is /usr/local/bin/fish (alternatively /usr/ports/shells/fish). Thank the whereis command for helping me figure that out.

[Danny Schoemann]

This worked on an ancient Fedora release 10 (Cambridge) box. Thanks.

[Liam Dawson]

-1: using sudo is not relevant to the question and is dangerous advice for common usage.

[BertC]

This worked for me also, but can anybody explain what the "ssh-agent /bin/sh" does?

[Fl_ori4n]

RUN ssh-agent sh -c 'ssh-add /root/.ssh/id_rsa' worked for me in a dockerfile