When the system reboots, quickly remove the USB installation drive. If you leave it in, the BIOS may boot right back into the installer, forcing you to reinstall again.
Since the Official pfSense Download Page now serves newer versions like 2.7.x or 2.8.x, you can find 2.5.1 through these community-maintained archives: Pfsense 2.5.1 Download Iso
Because pfSense has evolved past the 2.5.x lifecycle, obtaining older ISO files requires navigating official repository archives. Avoid downloading ISO files from untrusted third-party forums or file-sharing sites, as these images can easily be backdoored with malicious routing scripts. Steps to Acquire the Archive Image: Navigate to the official Netgate or pfSense website. When the system reboots, quickly remove the USB
The package manager in 2.5.1 may attempt to pull updated packages built for newer core OS structures, leading to dependency breaking. Lock or manually manage package configurations. Lock or manually manage package configurations
: Installing outdated versions is discouraged because they contain known vulnerabilities that are patched in later releases. Key Features and Changes in 2.5.1
If the version is archived, look for the official Netgate text-based mirror directory. 2. Choosing the Right Architecture and Installer When downloading, you will be presented with a few choices:
Insert a spare USB drive (minimum 4GB), select your extracted pfSense 2.5.1 ISO, and write the image to the drive.