Any thoughts?
Someone must be surely using IPv6 with a cellular connection...
Cheers!
Can you ping Google DNS via IPv6?
:ping 2001:4860:4860::8888
It's kinda odd how to setup. Since IPv6 is gives prefixes, while IPv4 is a single address, so MT handles them differently. On V7 at least... If you look at the APN settings under Interface>LTE>APN Profiles. Two settings are relevant: "IP Type" and "IPv6 Interface".
Maybe if you set the "IP Type" as "IPv4" instead of the default of "auto" in the "LTE APNs" dialog – EE may give you an IPv4 address...if the modem doesn't request a dual-stack configuration (which is what "auto" typically means). Thus, no need to mess with IPv6, which is sometimes wacky with LTE, as other poster reports.
If using "IPv4" as the "IP Type" in the APN DOES NOT work...and you IPv6 is all you got. You'd need to set "auto" as the IP Type again, AND
set the "IPv6 Interface" where the IPv6 traffic will go, typically a bridge. You can also create a VLAN interface for the LTE IPv6 traffic. Using a VLAN as the IPv6 interface, allows you add the IPv6 to a bridge if you were using "VLAN Filtering". (I believe you can set the IPv6 Interface in the LTE APNs to the lte interface itself, but I recall some bug in V7 where that didn't work at somepoint.)
Now once you could ping something like 2001:4860:4860::8888 from the router via LTE.... You run into NAT64 stuff as other poster notes. There are third-party tunnel brokers etc to avoid this, but very confusing/complex, without NAT64 on the Mikrotik.