FYI : IPv6 Prevented VPN Connection

[Anvil_Iron]

My wife uses VPN for work and one day she wasn't able to connect. I checked the router (Zyxel NR5103E) web-config and noticed the Primary/Secondary DNSv6 server addresses info were present which weren't before.

I tried disabling IPv6 in the WAN and LAN settings but internet service stopped.

I then enabled manual APN mode and changed from 3internet to Three.co.uk and restarted the router. After restart, the IPv6 info was N/A and the VPN was able to connect. VPN also connected when APN was set to 3internet with manual APN enabled.

The strange thing was when APN Manual Mode was disabled and router reset, IPv6 info was displayed. It looks like the router was obtaining IPv6 and IPv4 info from Three if manual APN mode is disabled. This could be the PDP Type being set to IPv4/IPv6 automatically by Three where as in manual APN mode, I have it set to IPv4 only.

[NT]

Thank you!  This also fixed my Hitachi TV & Amazon Firestick connectibity issues with teh same router & firmware version as yours!

[456]

Ok, HUGE issues here as well. All of a sudden, half of my devices WOULD NOT CONNECT to the internet. It seems that the issues stems from the router starting to assign ipv6 addresses to all the connected devices, instead of ipv4.

I was able to get all the devices re-connected by following the instructions from this thread.

HOWEVER - my speeds have now dropped from 500+megs to 100megs. Is there a way for the router itself to use ipv6 to connect to Three but for all my home devices to use ipv4 to connect to the router? 🙏

[dguru]

Thanks @Anvil_Iron . It didnt work for me unfortunately..

[CSmithyPx]

I just created an account to say thank you so much! I went back to using my 5g CPE PRO which is way way slower and is almost unusable now for some reason.
But this allowed me to go back to the router I got with the contract. Life saver

[jessicalouise]

This helped to fix my connection with my Nintendo switch. I've been frustrated with it for weeks now. Thanks for the help!

[456]

 Did anyone else's speed drop drastically after applying this change? My went down from 500+ to 100megs.

[Nimrodski]

The fix is fabulous (thank you Anvil_Iron if you're still lurking) but as per you 456, my download speed has seen an identical drop from c.500 Mbps to c.100Mbps. Upload speeds are conversely much improved (at 30/40Mbps)...

[456]

Three really need to sort this out. Unacceptable. @JonathanB 

[IC612]

Thanks so much for this! My WiFi printer, internet radio and Humax PVR had all stopped working, but having made these two changes they are all functioning again.

[Cymbalhead]

Same issue here. My ring doorbell and BT whole home mini discs suffered with problems 

I've applied the manual APN fix and things seem better, but I don't think it's fair to expect us to accept a drop from 600mbps to 100mbps as seems to be the case.