You can find the legacy pfSense-CE-2.5.1-RELEASE-amd64.iso at Internet Archive .
pfSense 2.5.1 was released on [insert date] and includes various bug fixes, security updates, and new features. You can check the official pfSense website for more information on the release. pfsense 251 download iso link
To help you get your firewall up and running, please let me know: You can find the legacy pfSense-CE-2
Disclaimer: Using old software versions may leave your network vulnerable to known exploits. Ensure proper firewall rules are in place if using for production. If you are setting this up, let me know: let me know: