You can try blocking QUIC.
QUIC (Quick UDP Internet Connections, pronounced quick) is an experimental transport layer network protocol developed by Google. QUIC supports a set of multiplexed connections between two endpoints over User Datagram Protocol (UDP), and was designed to provide security protection equivalent to TLS/SSL, along with reduced connection and transport latency, and bandwidth estimation in each direction to avoid congestion. QUIC's main goal is to optimize connection-oriented web applications currently using TCP. An experimental implementation is being put in place in Chrome by a team of engineers at Google.
What happens if QUIC is not blocked?
Chrome browsers have the QUIC protocol enabled by default. When users try to access Google applications using the Chrome browser, a session to a Google server is established using the QUIC protocol instead of TLS/SSL. QUIC is an experimental protocol at its early stages of development, and it uses proprietery encryption methods.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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