Posts: Ssh-Agent-Switcher

ssh-agent broken in tmux? I've got you!

A little over two years ago, I wrote an article titled SSH agent forwarding and tmux done right. In it, I described how SSH agent forwarding works—a feature that lets a remote machine use the credentials stored in your local ssh-agent instance—and how using a console multiplexer like tmux or screen often breaks it.

In that article, I presented the ssh-agent-switcher: a program I put together in a few hours to fix this problem. In short, ssh-agent-switcher exposes an agent socket at a stable location (/tmp/ssh-agent.${USER?} by default) and proxies all incoming credential requests to the transient socket that the sshd server creates on a connection basis.

In this article, I want to formalize this project by presenting its first actual release, 1.0.0, and explain what has changed to warrant this release number. I put effort into creating this formal release because ssh-agent-switcher has organically gained more interest than I imagined as it is solving a real problem that various people have.

December 26, 2025 · Tags: blogsystem5, software, ssh-agent-switcher, unix
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SSH agent forwarding and tmux done right

The SSH agent is a little daemon that holds your private keys in memory. This is particularly handy when your keys are protected by a passphrase: you can unlock and add your keys to the agent once and, from then on, any SSH client such as ssh(1) can interact with the keys without asking you for the passphrase again.

The SSH agent becomes even handier when you primarily work on a remote workstation over SSH. Under these circumstances, you will often need the remote workstation to establish SSH connections to other remote machines (e.g. to contact GitHub). In those situations, you can: copy your private keys to the remote workstation; generate different private keys on the remote workstation; or forward your SSH agent so that the remote workstation can leverage the keys from your client machine without them ever traveling over the network.

November 17, 2023 · Tags: blogsystem5, ssh-agent-switcher, unix
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