Traffic between ASA interfaces of same security level

Error: Deny inbound UDP from 192.168.109.77 to 8.8.8.8/53 due to DNS query

This problem occurs when you have configured 2 or more interfaces of Cisco ASA with same security-level. In such case, you need to configure and allow traffic between them.

(config)# same-security-traffic permit inter-interface

You can also perform the same section via ASDM.

Go to Configuration > Device Setup > Interfaces, and choose the Enable traffic between two or more interfaces which are configured with same security levels option.