Reach your NAS or home PC from outside the house

What the message looks like

Das NAS oder der Heim-PC ist von außerhalb nicht erreichbar / Home NAS not reachable from outside / NAS o PC di casa non raggiungibile da fuori

Common causes

• The router blocks incoming connections by default until a forward or VPN is set up.
• Your public IP address changes regularly, so the address you noted stops working after a while.
• The connection sits behind double NAT or provider-side NAT, so nothing from outside reaches your router.
• The port forward points to a wrong or since-changed internal IP address of the NAS.

Check

1. Check the NAS's internal address on the home network
   ping 192.168.178.20Copy
2. Check that a DynDNS name points to your current address (replace example.com with your name)
   nslookup example.comCopy
3. List devices on the home network to find the NAS address
   arp -aCopy
4. Look at the path to the internet. Several private hops suggest double NAT
   tracert example.comCopy

Fix

• Prefer a VPN: many routers offer a VPN server (for example WireGuard or IPsec). Connect to it and you are on the home network as if at home.
• If your connection has no public address of its own (provider-side NAT), ask the provider for one or use a VPN service.
• Changing address: set up a DynDNS service that points a fixed name at your changing address. The router or NAS reports the address itself.
• Only if needed, set up a port forward, give the NAS a fixed IP (reservation) first, and use a strong password, two-factor login and current firmware.
• Never expose admin pages or file shares (such as SMB) directly to the internet. Menu names vary with router.

FAQ

Is a port forward to my NAS dangerous?

It can be. Anyone on the internet can reach the open port, and attacks on known flaws are common. A VPN keeps the NAS invisible and is preferable.

What do I need DynDNS for?

Your public address usually changes. DynDNS ties a fixed name to the current address so you do not have to look it up each time.