Skip to main content

SSH Config

My default​

~/.ssh/config
# === Global (default) SSH settings for all hosts ===
Host *
    IgnoreUnknown UseKeychain
    UseKeychain yes
    ServerAliveInterval 30
    ServerAliveCountMax 10

  • IgnoreUnknown

    • Purpose: Tells the SSH client to ignore any options in the config file that it doesn’t recognize or understand.

  • UseKeychain

    • Purpose: On macOS, this tells SSH to use the system Keychain to store and retrieve passphrases for your SSH keys.

  • ServerAliveInterval 30

    • Tells your SSH client to send a “keepalive” message to the server every 30 seconds.
    • Prevents your SSH connection from timing out or being closed by firewalls or network equipment due to inactivity.

  • ServerAliveCountMax 10

    • If the server fails to respond to the keepalive messages, the SSH client will try 10 times (so, over 300 seconds, if interval is 30).
    • If there’s no response after 10 keepalives (so, 5 minutes), the SSH client will disconnect.

Host Blocks​

Servers​

~/.ssh/config
# Server 1 config
Host hostname
    HostName 192.1.1.100
    User username
    AddKeysToAgent yes
    UseKeychain yes
    IdentityFile ~/.ssh/id_user_ed25519
# IdentityFile ~/.ssh/id_ed25519_sk_rk_user_key6857

GitHub​

~/.ssh/config
# GitHub SSH config for user1
Host git-user1
    HostName github.com
    User git
    AddKeysToAgent yes
    UseKeychain yes
    IdentityFile ~/.ssh/user1_ed25519

# GitHub SSH config for user2
Host git-user2
    HostName github.com
    User git
    AddKeysToAgent yes
    UseKeychain yes
    IdentityFile ~/.ssh/user2_ed25519