Combine Multiple SSH Local Port Forwards Into One Command

Problem

You need to access multiple services on a remote EC2 instance locally — say, Chrome DevTools on port 18792 and an admin panel on port 8899. The naive approach is two terminals:

# Terminal 1
ssh -L 18792:localhost:18792 ec2-user@your-host -N
# Terminal 2
ssh -L 8899:localhost:8899 ec2-user@your-host -N

Two connections, two processes, easy to lose track of.

Solution: Stack Multiple -L Flags

One command handles both:

ssh -L 18792:localhost:18792 -L 8899:localhost:8899     -o ServerAliveInterval=30 -o ServerAliveCountMax=3     -N ec2-user@your-host

The -N flag tells SSH not to execute a remote command (just forward ports). -o ServerAliveInterval=30 keeps the connection alive.

Permanent Setup: ~/.ssh/config

Add this to ~/.ssh/config:

Host ec2-dev
    HostName your-ec2-ip-or-hostname
    User ec2-user
    IdentityFile ~/.ssh/your-key.pem
    LocalForward 18792 localhost:18792
    LocalForward 8899 localhost:8899
    ServerAliveInterval 30
    ServerAliveCountMax 3

Then:

ssh -N ec2-dev   # forwards all listed ports, no typing

Or if you also want a shell:

ssh ec2-dev      # opens shell + forwards ports simultaneously

-N vs -f

| Flag | Behavior |

|------|----------|

| -N | No remote command; process stays in foreground |

| -f | Goes to background immediately after authenticating |

| -N -f | Background process, no shell — ideal for port forwarding daemons |

For interactive use, -N (foreground) is easier to kill with Ctrl+C. For long-running setups, -N -f lets you close the terminal.

Check Active Forwards

# List all ssh processes doing port forwards

ps aux | grep "ssh -" | grep -v grep
# Check if a port is actually bound
lsof -i :18792