APM App tunnel & Client-side DNS redirector

Hello,

I'm currently testing app tunnels but I struggle with DNS. I'd like the user to keep the original application URL. I read in the documentation:

"Because app tunnels do not require administrative rights, some features of Network Access [...] are not available with app tunnels. For example, the application tunnel cannot easily resolve domain names in applications without a client-side DNS redirector, or modification of the system hosts file."

https://techdocs.f5.com/en-us/bigip-15-1-0/big-ip-access-policy-manager-application-access/configuring-app-tunnel-access.html

Do you have examples of "client-side DNS redirector" please?

F5 pre-sales told us about the F5 DNS relay proxy but I believe it's only enabled when the Network Access is mounted and the point of app tunnel is precisely not to mount the network access.

Thanks,