@coolsam07, Person who install jio ONT are hardware person. There knowledge is limited to regular installation only. You talk to technical person who is at server end. For that ask installation person to give name and contact of person who is at server end. Have word with them and ask them to disable DHCP at server end, as you want ONT as modem not router. (because you have your own router wherein you have functionality like VPN, DDNS and your own firewall.) Once DHCP is disabled from server end of your ONT connection, you can configure to Bridge Mode thus you doesn't have Double NAT enviorment.