To reset all firewall settings to their factory defaults, login to the router via the CLI (SSH) and run the following command:
cp /rom/etc/config/firewall /etc/config/firewall && reload_config
This will set your firewall settings to factory defaults, meaning that if you have any custom port forwards configured or if you had SSH/HTTP(S) rules enabled to accept input to the router from WAN, these custom (or modified) rules will become either wiped or disabled.
Logging in via CLI can be done in two ways - either using WebUI or via third party tools. To login to the CLI via WebUI, please login to WebUI and navigate to System > CLI. To login, enter "root" as the username and WebUI password.
If you need additional details about logging in to the router via CLI, please follow the instructions provided in our wiki page: