SSH Config Tips You Should Be Using

Key Insights

• Host aliases in ~/.ssh/config replace repetitive command-line flags with simple names like ssh prod
• ProxyJump handles bastion/jump host connections in a single command without manual tunneling
• Connection multiplexing (ControlMaster) reuses existing connections for near-instant subsequent logins

If you’re still typing full SSH commands with usernames, ports, and key paths, you’re working too hard. The SSH config file handles all of this.

Basic Host Configuration

# ~/.ssh/config

Host prod
    HostName 203.0.113.50
    User deploy
    Port 2222
    IdentityFile ~/.ssh/prod_ed25519

Host staging
    HostName 198.51.100.10
    User deploy
    IdentityFile ~/.ssh/staging_ed25519

Now ssh prod is all you need.

Jump Hosts

Host bastion
    HostName 203.0.113.1
    User admin

Host internal-db
    HostName 10.0.1.50
    User dbadmin
    ProxyJump bastion

Wildcard Patterns

Host *.prod
    User deploy
    IdentityFile ~/.ssh/prod_ed25519
    StrictHostKeyChecking yes

Host *.dev
    User developer
    StrictHostKeyChecking no

Keep Connections Alive

Host *
    ServerAliveInterval 60
    ServerAliveCountMax 3
    AddKeysToAgent yes

Multiplexing

Reuse existing connections for faster subsequent logins:

Host *
    ControlMaster auto
    ControlPath ~/.ssh/sockets/%r@%h-%p
    ControlPersist 600

Create the sockets directory: mkdir -p ~/.ssh/sockets

These configurations compound — once set up, SSH becomes nearly frictionless.