homelab-optimized/docs/admin/synology-ssh-access.md

🔐 Synology NAS SSH Access Guide

🟡 Intermediate Guide

This guide documents SSH access configuration for Calypso and Atlantis Synology NAS units.

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📋 Quick Reference

Host	Local IP	Tailscale IP	SSH Port	User
Calypso	192.168.0.250	100.103.48.78	62000	Vish
Atlantis	192.168.0.200	100.83.230.112	60000	vish

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🔑 SSH Key Setup

Authorized Key

The following SSH key is authorized on both NAS units:

ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBuJ4f8YrXxhvrT+4wSC46myeHLuR98y9kqHAxBIcshx admin@example.com

Adding SSH Keys

On Synology, add keys to the user's authorized_keys:

mkdir -p ~/.ssh
echo "ssh-ed25519 YOUR_KEY_HERE" >> ~/.ssh/authorized_keys
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

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🖥️ Connection Examples

Direct Connection (Same LAN)

# Calypso
ssh -p 62000 Vish@192.168.0.250

# Atlantis
ssh -p 60000 vish@192.168.0.200

Via Tailscale (Remote)

# Calypso
ssh -p 62000 Vish@100.103.48.78

# Atlantis  
ssh -p 60000 vish@100.83.230.112

SSH Config (~/.ssh/config)

Host calypso
    HostName 100.103.48.78
    User Vish
    Port 62000

Host atlantis
    HostName 100.83.230.112
    User vish
    Port 60000

Then simply: ssh calypso or ssh atlantis

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🔗 Chaining SSH (Calypso → Atlantis)

To SSH from Calypso to Atlantis (useful for network testing):

# From Calypso
ssh -p 60000 vish@192.168.0.200

With SSH agent forwarding (to use your local keys):

ssh -A -p 62000 Vish@100.103.48.78
# Then from Calypso:
ssh -A -p 60000 vish@192.168.0.200

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⚙️ Enabling SSH on Synology

If SSH is not enabled:

1. Open DSM → Control Panel → Terminal & SNMP
2. Check Enable SSH service
3. Set custom port (recommended: non-standard port)
4. Click Apply

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🛡️ Security Notes

• SSH ports are non-standard (60000, 62000) for security

• Password authentication is enabled but key-based is preferred

• SSH access is available via Tailscale from anywhere

• Consider disabling password auth once keys are set up:

  Edit /etc/ssh/sshd_config:

  PasswordAuthentication no
  

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🔧 Common Tasks via SSH

Check Docker Containers

sudo docker ps

View System Resources

top
df -h
free -m

Restart a Service

sudo docker restart container_name

Check Network Interfaces

ip -br link
ip addr

Run iperf3 Server

sudo docker run -d --rm --name iperf3-server --network host networkstatic/iperf3 -s

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📚 Related Documentation

• Network Performance Tuning
• Synology Disaster Recovery
• Storage Topology

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Last updated: January 2025