Improved certificate handling and resolved negotiation issues.

Downloading the ISO from the official Netgate portal is a critical security measure. Firewalls are the first line of defense for a network; installing a compromised operating system would render the entire network vulnerable. By forcing users to log in to retrieve the "pfSense 251" (25.01) link, Netgate provides a secure delivery chain. Users are also encouraged to verify the SHA256 checksum provided on the download page against the downloaded file to ensure the image has not been corrupted or tampered with during the transfer.

Before we dive into the download and installation process, let's take a look at some of the key features and improvements in pfSense 2.5.1: