miscellaneous-slides

SSH Config 201

SSH Config 201 - aliases, agents, identities and secrets

Different Aliases and Identities

Host raspberry pi.hole
  Hostname pi.hole
  IdentityFile ~/.ssh/id_ed25519
  User pi

Host github.com
  Hostname github.com
  IdentityFile ~/.ssh/github_ed25519
  User git

Host gitlab.com
  Hostname gitlab.com
  IdentityFile ~/.ssh/gitlab_ed25519
  User git

Using different SSH keys for different servers or services like your raspberry pi, github, gitlab, etc.

~/.ssh/config (continued)

Host *
  AddKeysToAgent yes
  IdentitiesOnly yes
  User michael

Advanced settings, catch-alls, defaults and wildcards.

Training Exercise

$ ssh github.com
Enter passphrase for key '/c/Users/michael/.ssh/github_ed25519':
PTY allocation request failed on channel 0
Hi mosterme! You've successfully authenticated, but GitHub does not provide shell access.
Connection to github.com closed.

$ ssh -v github.com
OpenSSH_9.2p1, OpenSSL 1.1.1t  7 Feb 2023
debug1: Reading configuration data /c/Users/michael/.ssh/config
debug1: /c/Users/michael/.ssh/config line 24: Applying options for github.com
debug1: /c/Users/michael/.ssh/config line 34: Applying options for *
debug1: Connecting to github.com [140.82.121.4] port 22.
debug1: Connection established.
debug1: identity file /c/Users/michael/.ssh/github_ed25519 type 3
debug1: identity file /c/Users/michael/.ssh/github_ed25519-cert type -1
debug1: Authenticating to github.com:22 as 'git'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: zlib@openssh.com
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: zlib@openssh.com
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: SSH2_MSG_KEX_ECDH_REPLY received
debug1: Server host key: ssh-ed25519 SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU
debug1: Host 'github.com' is known and matches the ED25519 host key.
debug1: Found key in /c/Users/michael/.ssh/known_hosts:3

Training Exercise (continued)

debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Will attempt key: github_ed25519 ED25519 SHA256:1pvzcZIoac8pFpJLiN0gsYI8KvX5u746m5Ja7rGuUmE explicit
debug1: SSH2_MSG_EXT_INFO received
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: github_ed25519 ED25519 SHA256:1pvzcZIoac8pFpJLiN0gsYI8KvX5u746m5Ja7rGuUmE explicit
debug1: Server accepts key: github_ed25519 ED25519 SHA256:1pvzcZIoac8pFpJLiN0gsYI8KvX5u746m5Ja7rGuUmE explicit
Enter passphrase for key '/c/Users/michael/.ssh/github_ed25519':
debug1: Enabling compression at level 6.
Authenticated to github.com ([140.82.121.4]:22) using "publickey".
debug1: channel 0: new session [client-session] (inactive timeout: 0)
debug1: Entering interactive session.
debug1: pledge: filesystem
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug1: pledge: fork
PTY allocation request failed on channel 0
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
Hi mosterme! You've successfully authenticated, but GitHub does not provide shell access.
debug1: channel 0: free: client-session, nchannels 1
Connection to github.com closed.
Transferred: sent 2300, received 2580 bytes, in 0.2 seconds
Bytes per second: sent 11654.8, received 13073.6
debug1: Exit status 1

1Password SSH Agent

Requirements (Windows)

Configure 1Password

  1. Configure Windows Hello
  2. (Security) Unlock using Windows Hello
  3. (Developer) Use SSH agent
  4. (Developer) Ask approval for each new: application

Using Windows Hello Use SSH agent

1Password SSH Keys

1Password SSH Keys

Configure Git (Windows)

Configure the core.sshCommand in your Git config to use Microsoft OpenSSH.

$ git config --global core.sshCommand "C:/Windows/System32/OpenSSH/ssh.exe"

You can also manually edit your .gitconfig file.

[core]
  sshCommand = C:/Windows/System32/OpenSSH/ssh.exe

 

 

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