Find out what DNS your Unifi Security Gateway is using

If you want to find out, which DNS servers your Security Gateway is using right now, ssh into your USG and run

show dns forwarding nameservers

which will print something like

-----------------------------------------------
   Nameservers configured for DNS forwarding

-----------------------------------------------

217.0.43.65 available via 'ppp pppoe0'
217.0.43.81 available via 'ppp pppoe0'