Which of the following is NOT a recommended countermeasure against sniffing attacks?

Using FTP for transferring files is not a recommended countermeasure against sniffing attacks because FTP transmits data in plaintext, which makes it vulnerable to interception. Sniffing attacks involve capturing network traffic, and if the data is sent unencrypted, attackers can easily read sensitive information, such as usernames and passwords.

In contrast, using SSL (Secure Sockets Layer) provides a secure channel for communication, ensuring that the data sent over the network is encrypted and protected from eavesdropping. Encrypting sensitive files further enhances security by making the data unreadable to unauthorized parties, even if they manage to capture it. Implementing MAC (Media Access Control) filtering can also add a layer of security by controlling which devices are allowed to connect to the network, making it harder for an attacker to introduce a sniffing device.

Overall, the emphasis is on using secure methods and protocols that protect data in transit, highlighting why relying on FTP is insufficient for countering sniffing attacks.