How to prevent open DNS resolver by setting up Symantec Firewall？

We can prevent PC running open DNS resolver by changing firewall setting. We’ll take Symantec as an example, please follow these step.

Turn on Symantec Endpoint Protection, click Network threat Protection, and then select configure firewall rules

In configure firewall rules dialog box , click Add

In Add Firewall Rule

Give the rule name and type in text box, for example: DNS_resolver

Select Block this traffic

Click the tab for Ports and Protocols

choose UDP from dropdown for Protocol

Type 53 In the Local Ports field

Choose Incoming in dropdown for Traffic direction

Click OK

Check that “DNS_resolver” has shown in configure firewall rules dialog box

Click OK