Final answer:
Secure cross-domain solutions are used to transfer files between JMN and NIPRNet environments, tailored to ensure security during the transfer of sensitive information like an IP mission block list.
Step-by-step explanation:
The tool used to transfer files between the Joint Mission Network (JMN) and Non-secure Internet Protocol Router Network (NIPRNet) environments is commonly a secure cross-domain solution that enables users to move data while maintaining the integrity and security required by such segregated systems. Security is paramount when transferring sensitive information like an IP mission block list file, and the exact tool may vary depending on the security protocols and software approved for use within an organization's IT infrastructure.
These tools typically involve secure file transfer protocols that could include manual review and sanitization processes or automated transfer mechanisms with robust security features. However, due to the sensitive nature of this topic, the specific names of such tools are often not discussed in open forums to maintain operational security.