CompTIA Network+ Practice Test

When the Maximum Transmission Unit (MTU) is set too low in a network, packets are unable to leverage the optimal size for efficient data transmission. The smaller size means that more packets need to be created to transmit the same amount of data. As a result, this can lead to more frequent fragmentation of packets, where larger packets are broken down into smaller ones to fit the MTU limits. Each time a packet is fragmented, there is additional processing overhead involved for both the sending and receiving devices, which can slow down overall transmission speeds.

Fragmentation can cause increased latency and higher chances of packet loss, as partially transmitted packets may need to be resent. This scenario ultimately reduces the performance of the network. Thus, configuring an appropriate MTU size is critical to maintaining efficient communications across a network.

The other options do not accurately reflect the impacts of a low MTU setting. Lower MTU does not inherently lead to faster transmission; in fact, it tends to have the opposite effect. It does not enhance network security directly, and devices cannot automatically adjust their MTU settings to correct for improper configurations without manual intervention or specific protocols designed to do so.