China Telecom & NAT WRT1900ac

I have been trying to connect to my Synology Diskstation via a remote connection (VPN, WebDAV etc) for months and nothing has worked. Someone on Reddit said that my LAN IP should match my IP that is displayed when I use https://whatismyipaddress.com/. It doesn't match, so that probably means China Telecom are using a NAT. Does anyone have any experience with fixing this issue?

Any help would be much appreciated.

You need at least one globally routed IPv4 or IPv6.
Check from the router to be sure:

ip address show 

The reserved ranges:
https://en.wikipedia.org/wiki/Reserved_IP_addresses

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someone on Reddit was almost right.

you should be looking at the WAN IP.

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WAN IP doesn't appear to be a thing on this router?See here

Sorry, I don't know what any of that means? How do I check?

WAN is always a "thing", unless you run it as a access point.

Are you running openwrt on your device ?

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@jonbennsion, welcome to the community!

  1. You don't have to make a reply to each person in series, we can all see.
  2. I don't know why you showed us a Google search page - and the extra code in the search is concerning
  3. We know there is a WAN IP, otherwise it isn't a router
  4. Please confirm you're running OpenWrt

You go to whatismyip.com and verify your WAN IP matches, as we've noted to you.

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Seems, illogically, the WAN IP is shown on the troubleshooting page.

https://community.linksys.com/t5/Wireless-Routers/WRT1900ac-router-WAN-IP/td-p/827276

But, if you find it there, you're not running openwrt.

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The reason I included the google link was because it seems my router does not have a WAN address displayed anywhere in the admin page. I am not running openwrt.

Please find the appropriate support forum for the manufacturer of your hardware/firmware. This forum is for OpenWrt support.

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My Public IPv4 address that I looked up using whatismyip, does not match what is shown in the troubleshooting section of the router admin page.

then you're probably NATed.

There are ways to get around it, but it might cost you some money, unless you've got a buddy with a public IP :wink:

You might consider switching to openwrt, but it'll not solve the problem at hand.

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If your ISP's modem is on "routing mode", you should switch it to "bridge mode", which is necessary (but not sufficient) if you want a public IP on router's WAN.

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Most likely it's CGNAT in play here.

Essentially you'll need a global routable IP to make your internal service available over the internet. Be it native IPv6(China Telecom enables this in some areas), or in IPv4 world solutions like VPN/ngrok etc.

It was a NAT. They have now given me a public IP address that has allowed me to access using WebDAV. Thanks for the help!

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