Hyper Backup cannot connect to remote Hyper Backup Vault over Tailscale, even though DSM and port 6281 are reachable

Synology
1

Hi everyone,

I’m trying to set up an off-site Hyper Backup using Tailscale, but I’m stuck with a problem that I can’t explain.

My setup

  • Source NAS: Synology DS1522+

  • Destination NAS: Synology DS420+

  • Both running DSM 7.3.2

  • Hyper Backup: 4.2.2-4262

  • Hyper Backup Vault: 4.2.2-4262

  • Latest Tailscale package installed on both NASes

  • Both NASes authenticated to the same Tailscale account/tailnet

  • Destination NAS is now at a friend’s office (different Internet connection)

  • No port forwarding (this is intentional, I’m using Tailscale)

What works

  • I can access the destination DSM through its Tailscale IP:

    https://100.x.x.x:5001

  • The destination NAS appears as Connected in Tailscale.

  • Hyper Backup Vault is running.

  • DSM firewall is disabled.

  • SMB works normally.

  • From my Mac (connected to Tailscale), the following succeeds:

    nc -vz <tailscale-ip> 6281

    so TCP port 6281 is definitely reachable.

What does NOT work

In Hyper Backup, when creating a new Remote NAS Device task:

  • Server: Tailscale IP

  • Port: 6281

  • Transfer Encryption: tried both On and Off

As soon as I press Log In, I immediately get:

Failed to connect to the backup destination…

It never reaches the point where it asks for credentials or lists the destination shared folders.

Exactly the same happens if I edit an existing Hyper Backup task and only replace the destination IP with the Tailscale IP.

Things I’ve already tried

  • Verified correct Tailscale IP

  • Verified Hyper Backup Vault is running

  • Disabled DSM firewall

  • Trusted and ignored the destination certificate

  • Tried with Transfer Encryption both enabled and disabled

  • Created a brand new administrator account and tried with that

  • Upgraded Tailscale to the latest version on both NASes

  • Confirmed both Hyper Backup and Hyper Backup Vault are on identical versions

  • Rebooted both NASes

  • Stopped and restarted Hyper Backup Vault

  • Checked DSM Log Center during every connection attempt

Interesting observation

Nothing is written to Log Center when Hyper Backup fails.

That makes me think the connection may not even reach Hyper Backup Vault, even though:

  • DSM over Tailscale works

  • TCP port 6281 is reachable

  • Hyper Backup Vault is running

Questions

  1. Has anyone seen Hyper Backup fail at the Log In stage while DSM and port 6281 are both reachable over Tailscale?

  2. Is there any additional DSM service, package permission, or Tailscale configuration that Hyper Backup requires beyond basic connectivity?

  3. Is there a log specific to Hyper Backup Vault that I’m missing?

  4. Is there a known issue with DSM 7.3.x + Hyper Backup 4.2.2 + current Tailscale?

I’d really appreciate any ideas. At this point it feels like I’ve eliminated all of the obvious networking issues, but Hyper Backup still refuses to authenticate to the destination.

Thanks!

2

Arghhh, just had to enable outbound connections $%#@%^$#@^#@

1 Like