Hi SumaN,
IAP proxies all DNS requests for the clients in this mode.
If you configure an asterisk (*) instead of a domain name in the enterprise domain list, all DNS requests areforwarded to the default DNS server of the client. If you want all DNS requests to be processed by the DNS server of the client, configure an asterisk (*) in the enterprise domain setting.
So, we have the following options:
1. Configure the DNS server to be same for IAP & Client.
2. In case we do not have DNS configured for the IAP, then configure an asterisk (*) in the enterprise
domain settings which will allow all the DNS request to be processed by the DNS server of the client.