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New Contributor

DNS database ipv4 not working when ipv6 is enabled.

Hi there


We're running an office with about 50 employees.

Both Mac and Windows PCs

Since we're using Azure AD (without Directory Service), I've created a local DNS database where I can forward fx fw-01.FQDN to as well as switch-01.FQDN to etc.
This works wonders - when ipv6 is not enabled.

Once ipv6 is enabled on the fortigate F80 with 7.2.5 build 1517, it stops working. 

By disabling ipv6 on a device, fx a Windows machine, it works again.

I cannot for the life of me, figure out how or what I need to change/setup to make some sort of forwarding, when an ipv6 dns address is acquired.

I've attached a few screenshots of our settings, in hopes that it is sufficient information - if not, I'll provide whatever is needed.

Is someone able to point me towards the correct area where to search, what to search for, or maybe a post on the forum that I've missed?

Internal interfaceInternal interface


Internal interfaceInternal interface








DNS serverDNS server




Hi @Fastspeed,


Can you provide a network diagram which explain the traffic flow? It can be a limitation as there is no IPv6 options under DNS database. 



New Contributor

Hi hbac
Thank you for replying.
As our setup is about to change (which I was initially unaware of) the need for resolving from a local database will no longer be needed.
As such, I'd like to cancel the request for help, but I am unsure on how to.