Tailscale between two Synology NAS

Support
1

My son and I purchased Synology NASes and connect them with Tailscale.

I do one-way Synchthing of a directory but it is soo slow. A brief search of the forum indicate the problem may be personal.

What could I be doing wrong?

2

Please start with screenshots of the UI on both sides, with the other Device expanded.

3

I hope I scrubbed unique identifiers..

Source is RR2

RR2
RR21918Ă—1538 342 KB

Target is RR1

RR1
RR11892Ă—1384 322 KB

4

That’s a pretty slow Upload rate on the RR2 Device, with a correspondingly poor Download Rate from the RR1 Device.

EDITED: This was a dumb question, my apologies: Are they connected over the Internet?

I am also curious about the number of connections. Did you change any of the defaults for this? Please post a screenshot of Actions / Settings / Connections. If you made any changes in Advanced Settings previously, please post a screenshot of that as well.

5

I can tell it is using IPv4 from the first screenshot, because of the dot and 4 at the end of the address.

Is the first octet (i.e. the number before the first dot) of the address 100? If it isn’t, then it’s not connected through Tailscale.

Tailscale’s IPv4 addresses from the CGNAT range, which AFAIK Syncthing does not announce. Tailscale’s IPv6 addresses are ULA addresses which Syncthing does announce.

Have you checked that your firewall(s) have the appropriate ports opened? Because there are 2 signs that is not the case:

  • The ports look translated
  • Connection is using QUIC, which is lower priority by default, and is used for UDP holepunching
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