Synology NAS problems with WAN

So I’m up and running with my Syncstore on my Synology NAS using the Synology WebDav.

All good on my LAN but when I go outside my LAN and try to sync on my iPad I get a time out every time. If I take the iPad back in to my LAN it works.

So I’m presuming this is something to do with the address in my DT WebDav sync set up. The only thing I could get to work was in the form: xyzserver.local:5006/andyfolder/SyncStore*
which as I say works fine in my LAN but not my WAN.

Any Synology DT experts?


You have to set up DDNS and Port forwarding. Both described online at Synology and elsewhere, since it is a general network issue: your NAS does not have a public IP address because it is behind the router.

I use Zerotier. DO you know if DT will work with Zerotier? Or do I have to manually set up as you say?

Synology NAS have a tool called Ez-Internet (or similar name) that can do all the stuff auto-magically, even open and redirect ports in most of the routers. Apart the fact that is all extensively documented in Synology website.

1 Like

After a cursory look at Zerotier’s website, I second @rfog’s advice. Read the Synology documentation.
Personally, I’d stay away from anybody promising “it just works” in the context of networking. Especially, if they mention NAS in their marketing blurb but don’t talk about it in their knowledge base.

Zerotier punches a port hole and my iPad has connection with my NAS and indeed any other devices on my network including all my computers that have the Zerotier app instslled. It does indeed ‘just work’.
I’m not sure why DT cannot take advantage of that…maybe because DTTG needs to mount the sync store drive?
Anyhow this was to have pdf’s available on my iPad and I use File Browser Go (a very useful app) on my iPad which uses Zerotier successfully to access my NAS and a folder with all my pdf’s on there.

I’ll investigate further.

What you might want to try is use a laptop to connect from the outside (i.e. make sure that the laptop is not connected to your WLAN/router!) to the WebDAV server on the NAS by entering the exact same address into the “connect to server” field on the laptop that you use for your sync settings on the iPad.

It boils down to a connectivity issue, and those are notoriously difficult to debug from an i*OS device, because they do not provide tools.

Also, from your description, I’m not sure if you have PDFs in a NAS folder which you index in DT and consequently can also view in File Browser Go on the iPad or if the sync location on our NAS and the PDF folder you mention above are two different entities. It would help if you could describe the setup in more clarity and detail.

If that’s your cup of tea, go with it. Personally, I’d certainly not allow any third party to “punch holes” in my router, thank you very much. This is sensible stuff and I prefer to have control over that. Synology NAS devices are perfectly capable of opening the required ports via UPnP themselves, btw.

Thanks for this advice- yes putting a laptop outside is a good way to go to investigate. Will do this.

Regarding my ‘PDF folder’: basically I have gone with a folder on my NAS with all my PDF’s. I was using a DT database for managing my PDF library but there is no real advantage if I have Zerotier and a NAS- in fact it’s more convenient in some ways.

Regarding Zerotier, as you say each to their own. I love it for many reasons, most of all - it just works:)
Well…you’re caveat is right… except it doesn’t seem to work with DT.

So basically, you have

  • a folder with PDFs on your NAS which you can access from the WAN via your iPad/iPhone. How? I.e. which protocol do you use (SMB, AFP, NFS, …?)
  • and one more database(s) on your NAS which you want to access via WebDAV. That seems to work as long as you’re inside your LAN, but not when you’re outside.

If that’s true, one would still need more DETAIL to be able to help you. AFAICT, Zerotier is DDNS that also does port forwarding (that’s what I guess, since their website is deliberately obscure on that). So your NAS should have an external name which you should be able to look up in your Zerotier console. Does it?
It should also have a port number there - does it?
This port number should be mapped to port 5006 and your NAS’s ip address in your router. Is it?
If you enter the external name of your NAS and the external port number in the sync settings of your iPad (something like:, where xxxx is the port number) and your correct user name/password for the WebDAV service on the NAS - what do you get on the iPad? Any error messages?
If your router provides any error or warning messages, what do they say?
What do the log files of your NAS tell you: connection attempt from the WAN visible? Denied because of …? Successful, but …?

See my answers in italics

This is a method used among the Synology crowd (though I don’t use it as I’m not syncing to WebDAV off-network)

By device, you mean “NAS”? Or your desktop?
Regardless, I’m out now. You should ask the people who promise you that “it just works”. Since reality has just proven them wrong.
On a side note: Even if it all seems so lovely and easy, I still think that you should not use this service (or any similar one). First, for the obvious reason that “it just works” is not true. Second, because these guys don’t tell you what they’re doing. So it does not work and you have no chance to fix it, because you don’t even know the port number to connect to. Third, because one simply does not install third party software inside a network that punches holes in it without knowing exactly what one is doing and what they are doing. And fourth, because all of the things they promise you (and you perhaps pay for) you can get for free with your NAS anyway. As @BLUEFROG said already: Synology NAS problems with WAN

1 Like

I appreciate your advice but you are not correct and are advising in a very narrow way I feel. So thanks but if you are “out” that’s fine!
Really you come across as an expert but networking is a vast and complex field and we should never throw accusations around about what we feel is THE ONLY WAY IT CAN BE DONE. There are many ways as you well know. You may have a preference but that’s all it is. Zerotier is not some shady company as you imply. It’s used everyday by millions of secure and happy people. You are throwing accusations but they are completely unfounded.

I’m out too. I’ll carry on using Zerotier.

That’s why I said “TL,DR;”
For the record: I tried to walk you through the necessary steps to fix your problems. You choose to not take them. That’s your prerogative. Mine is to not fall for marketing blurb and to remark on security issues as I see fit.
I wasn’t accusing anybody but pointing out possible problems.

1 Like

Hi, Fred,
When away I connect to my WebDAV SyncStore on Synology via VPN over private DSL router. Has been working reliably over a few years, surviving router and Synology hardware upgrades.

Hi Axel
Thanks for that, appreciated. Would you mind telling me what form your URL address is in the DT preferences for the WebDav. Mine is:


which somehow doesn’t seem right?

Hi, sorry for late reply


For security reasons I created a separate WebDav user for syncing.