Synology NAS DSM7 - services don't work

I have had 2 synology NAS in my tailscale network - everything has been working great for about 3 months - have upgraded to DSM 7 and now some of the services don’t seem to work

I can log in, I can map network drives, I can use synology drive using tailscale ip address but other features don’t work where previously they did using the ip address (eg hyperbackup, drive sync)

I have uninstalled and reinstalled, and seem to be facing same issues

Is anyone else facing this? Have made sure that the firewall ports for those apps are open on NAS
Its off that some work and some don’t
Thanks for suggestions

Does your Synology NAS support tun device?

I am not sure what that means actually

I have a DS920 and a DS918

Can you check /dev/net/tun ?

On DSM 7 we currently use a userspace implementation of Tailscale and don’t modify the system’s routing table. So with DSM 7 you can connect TO your Synology, but you can’t connect out FROM your Synology to other stuff.

We might be able to make it work yet on DSM 7 but haven’t finished.

Thanks for the explanation - I am currently using TS and ZT and the combo seems to cover everything between them
Hopefully can get TS back to the role of covering everything it was before
Cheers