The DMZ Gateway configuration file can be found at ( <InstallDir>\conf\DMZGatewayServerService.conf) by default, and it can be edited to fine-tune your DMZ Gateway deployment for specific situations.

The config file has a number of configurations in place already, so the best advice is to find the existing properties in the configurations file and copy the format. 

Example:

In the # Additional Java parameters section, add the flood protection property at the bottom, with the next index number.

# Additional Java parameters. Add parameters as needed starting from 1.
# By default, use the server Virtual Machine.
wrapper.java.additional.1=-server
wrapper.java.additional.2=-DDMZSharedConfigurationDirectory=%DMZ_SHARED_CONFIG_DIRECTORY%
wrapper.java.additional.2.stripquotes=TRUE
wrapper.java.additional.3=-Djava.ext.dirs=bin/jre1.8.0_45/lib/ext
wrapper.java.additional.4=-Dfile.encoding=UTF-8
wrapper.java.additional.5=-DDMZBufferPoolBufferSize=262144
wrapper.java.additional.6=-DEnableConnFloodProtection=False