For successful TFTP operations, which setting is crucial on the server side?

For successful Trivial File Transfer Protocol (TFTP) operations, firewall settings on the server side are crucial because TFTP uses specific UDP ports for communication, primarily port 69. If the firewall is configured to block this port or any associated UDP traffic, TFTP operations will fail as the server will be unable to send or receive the file transfer requests. Proper firewall settings ensure that TFTP traffic can flow freely between the client and server, allowing for successful file transfers.

While DNS configuration, IP address assignment, and access control lists are important for network communication and security, they are not directly responsible for TFTP's operational success as firewall settings are. DNS might help in resolving names to IP addresses but isn't a requirement for basic TFTP functionality. IP address assignment is vital for establishing communication but assumes that the firewall is already permitting the necessary traffic. Access control lists could restrict traffic based on security policies; however, they need to be correctly configured to allow TFTP traffic, which ultimately ties back to firewall settings.