What protocol is used for downloading Antivirus and IPS packages from FortiGuard?

The protocol used for downloading Antivirus and IPS packages from FortiGuard is TCP. This is because TCP (Transmission Control Protocol) is a reliable, connection-oriented protocol that ensures that data is delivered accurately and in the correct order. When FortiGate appliances need to retrieve critical updates such as Antivirus and IPS (Intrusion Prevention System) signatures, they do so over TCP to ensure that these updates are transmitted without errors or packet loss.

Using TCP for such updates is especially important since these updates can be large and the integrity of the update is paramount for maintaining the effectiveness of network security. In contrast, protocols like UDP (User Datagram Protocol) are not suitable for this purpose, as they do not guarantee the delivery of packets or the order in which they arrive. HTTP (Hypertext Transfer Protocol) is often used as a higher-level protocol that operates over TCP for web-based communications, but it is not as directly applicable in this context. ICMP (Internet Control Message Protocol) is used for diagnostic or control purposes, such as pinging a server, and does not support the transfer of files or updates, making it unsuitable for this task.