Configuring the DNS Preprocessor

Note	This section applies to Snort 2 preprocessors. For information on Snort 3 inspectors, see https://www.cisco.com/go/snort3-inspectors.

Procedure

Step 1

Choose Policies > Access Control, then click Network Analysis Policy or Policies > Access Control > Intrusion, then click Network Analysis Policies.

Note	If your custom user role limits access to the first path listed here, use the second path to access the policy.

Step 2

Click Snort 2 Version next to the policy you want to edit.

Step 3

Click Edit ( edit icon ) next to the policy you want to edit.

If View ( View button ) appears instead, the configuration belongs to an ancestor domain, or you do not have permission to modify the configuration.

Step 4

Click Settings in the navigation panel.

Step 5

If DNS Configuration under Application Layer Preprocessors is disabled, click Enabled.

Step 6

Click Edit ( edit icon ) next to DNS Configuration.

Step 7

Modify the settings as described in DNS Preprocessor Options.

Step 8

To save changes you made in this policy since the last policy commit, click Policy Information, then click Commit Changes.

If you leave the policy without committing changes, cached changes since the last commit are discarded if you edit a different policy.

If you want to generate intrusion events, enable DNS preprocessor rules (GID 131). For more information, see Setting Intrusion Rule States and DNS Preprocessor Options.
Deploy configuration changes.