airtel fiber on bridge mode ?

Possible to enable this bridge mode thing on a zyxel PMG5617-R20B router? Airtel pushed some update to the router few weeks ago and now I cannot change dns. There was an Apply button next to the dns field but they removed it now. What's their email btw for requesting to enable bridge and shit?
 
But I thought when bridge mode in enable the airtel ont won’t be connected to internet at all because it only works as modem . That means airtel onts WiFi will also not work .
It should not. Check if you're behind double NAT. Go to whatismyip.com and see if that matches the WAN IP of your non airtel router.
 
OP what is your ONT model and is the bridge mode working fine now?I am also trying to the same setup for my home network!
 
OP what is your ONT model and is the bridge mode working fine now?I am also trying to the same setup for my home network!
Mine is Zte model no I don’t remember and yeah after sending mail to net@airtel.com they will create a complain service no and then local technician will call you and ask your problem and then you will have to explain him that you need bridge mode enabled on your router . Then that technician will call the noc team and get it done . Also it will be active on lan port 4