Use Decryption Policy rules to define the traffic you
decrypt and the traffic you choose not to decrypt because of regulations,
business reasons, or privacy reasons.
A Decryption policy rule allows you to define traffic
that you want the firewall to decrypt and to define traffic that
you choose to exclude from decryption
because the traffic is personal or because of local regulations,
Attach a Decryption profile to each Decryption policy rule to
enable certificate checks, session mode checks, failure checks,
and protocol and algorithm checks, depending on the profile. These
checks prevent risky connections, such as sessions with untrusted
certificate issuers, weak protocols, ciphers, and algorithms, and servers
that have certificate issues.
As a best practice, you should always block known dangerous URL Filtering categories such
as malware, phishing, dynamic-dns, unknown, command-and-control,
proxy-avoidance-and-anonymizers, copyright-infringement, extremism,
newly-registered-domain, grayware, and parked. If you must allow
any of these categories for business reasons, you must decrypt them
and apply strict Security profiles to the traffic.
URL categories that you should always decrypt if you allow them
include: online-storage-and-backup, web-based-email, web-hosting, personal-sites-and-blogs,
In Security policy, block Quick UDP Internet Connections (QUIC) protocol unless
for business reasons, you want to allow encrypted browser traffic.
Chrome and some other browsers establish sessions using QUIC instead
of TLS/SSL, but QUIC uses proprietary encryption that the firewall can’t
decrypt, so potentially dangerous traffic may enter the network
as encrypted traffic. Blocking QUIC forces the browser to fall back
to TLS/SSL and enables the firewall to decrypt the traffic.