"Access Denied" for pages on my own NAS when on O2 Mobile

[MillmoorRon]

After restarting my phone (which is necessary occasionally) I get blocked from my own html pages (hosted on my NAS) when using mobile data. It works fine over wi-fi.

The "Access Denied" page I get instead states:

This page has been blocked for either a legal or technical reason.
The most likely cause is that you have received a fraudulent text or email and we are blocking the website you are being asked to go to.
If you believe this is not the case or have a different issue then please contact customer services or use your MyO2 account through the app or online.
If you’re still unsure, check out https://community.O2.co.uk.

It eventually comes back but I'm not sure why. I need to be able to access these pages when I'm away from home.

Any suggestions as to what is causing this and how to stop it?

[madasaf1sh]

@MillmoorRon 

How are you accessing the NAS, is it over a rDNS service or direct via IP? 

[MillmoorRon]

It's a dynamic DNS (DuckDNS.org) and my NAS updates automatically when my IP address is changed by ISP.

[MI5]

@MillmoorRon 

Lots of reported issues with Duck lately relating to security.

[madasaf1sh]

@MillmoorRon 

Yep DuckDNS.org, seems to get blocked across a number of ISP's every so often, as although its free, it is used by people trying to commit fraud and scams, so a lot of RBL (Realtime Blocklists) are sending these to be blocked. 

[MillmoorRon]

How do I unblock it?

It fixed itself within an hour or so on the previous occasions, but hasn't this time!

[MI5]

Change your provider @MillmoorRon 

As we've said, Duck is a risk.

[madasaf1sh]

@MillmoorRon 

You need to contact DuckDNS as they are only ones who can do anything... And it will keep getting blocked..  

Have a look at setting up your own rDNS services using Linode (you will have to pay for computing but have a look at NetworkChuck he usually has a promo for $100 dollars credit).

[MillmoorRon]

I have a domain registered with Ionos. It turns out that they have an API which allows DDNS. This feature is well documented but not mentioned in the account settings. It needs to be activated first, and I only found out about it after some Googling! Hopefully this will sort my issues.

[Oxonian]

@MillmoorRon 

For five years, I was website manager for a small registered charity ; our domain registration and website hosting was with Ionos. I am sure that they will sort you out, as their customer service and technical staff were excellent. 

Ionos are not cheap, but my experience is that you get first class support from them.