Follow the instructions to configure the ESET firewall to function like a new installation.
Press the F5 key to open Advanced setup.
Click Network Protection → Firewall and click the default icon for the section settings you want to revert (Basic in this example).
Press the F5 key to open Advanced setup.
Click Network Protection → Firewall, expand Advanced and click Edit next to Rules.
Select the check box next to Show built in (predefined) rules at the bottom left side of the Firewall rules window to view built-in rules.
Make sure that you can view hidden files and folders.
Navigate to the appropriate directory for your operating system as shown below:
C:\ProgramData\ESET\ESET Security
Delete the following files to permanently remove all firewall rules:
epfwdata.bin
EpfwTemp.dat
EpfwUser.dat