A Cisco ASA is configured for TLS proxy. When should the security appliance force remote IP phones connecting to the phone proxy through the internet to be in secured mode?
A. When the Cisco Unified Communications Manager cluster is in non-secure mode
B. When the Cisco Unified Communications Manager cluster is in secure mode only
C. When the Cisco Unified Communications Manager is not part of a cluster
D. When the Cisco ASA is configured for IPSec VPN
https://www.cisco.com/c/en/us/td/docs/security/asa/special/unified-communications/guide/unified-comm/unified-comm-overview.html
The ASA supports TLS proxy for various voice applications. The TLS proxy running on the ASA has the following key features:
The ASA forces remote IP phones connecting to the phone proxy through the Internet to be in secured mode even when the Cisco UCM cluster is in non-secure mode.
The TLS proxy is implemented on the ASA to intercept the TLS signaling from IP phones.
The TLS proxy decrypts the packets, sends packets to the inspection engine for NAT rewrite and protocol conformance, optionally encrypts packets, and sends them to Cisco UCM or sends them in clear text if the IP phone is configured to be in nonsecure mode on the Cisco UCM.
The ASA acts as a media terminator as needed and translates between SRTP and RTP media streams.
The TLS proxy is a transparent proxy that works based on establishing trusted relationship between the TLS client, the proxy (the ASA), and the TLS server.