/mcp• Update the PIN by logging into Extension Mobility or Directory access on the phone. • Update the password by logging into Cisco Jabber, Cisco Unified Communications Self Care Portal, or Cisco Unified CM Administration. For more information on how to generate the report, see the Cisco Unified CM Administration Online Help. Signaling Encryption Signaling encryption ensures that all SIP and SCCP signaling messages that are sent between the device and the Unified Communications Manager server are encrypted. Signaling encryption ensures that the information that pertains to the parties, DTMF digits that are entered by the parties, call status, media encryption keys, and so on, are protected against unintended or unauthorized access. Cisco does not support Network Address Translation (NAT) with Unified Communications Manager if you configure the cluster for mixed mode; NAT does not work with signaling encryption. You can enable UDP ALG in the firewall to allow media stream firewall traversal. Enabling the UDP ALG allows the media source on the trusted side of the firewall to open a bidirectional media flow through the firewall by sending the media packet through the firewall. Hardware DSP resources cannot initiate this type of connection and, therefore, must exist outside the firewall. Tip Signaling encryption does not support NAT traversal. Instead of using NAT, consider using LAN extension VPNs. Media Encryption Media encryption, which uses Secure Real-Time Protocol (SRTP), ensures that only the intended recipient can interpret the media streams between supported devices. Media encryption includes creating a media master key pair for the devices, delivering the keys to the devices, and securing the delivery of the keys while the keys are in transport. Unified Communications Manager supports SRTP primarily for IOS gateways and Unified Communications Manager H.323 trunks on gatekeeper-controlled and non-gatekeeper-controlled trunks as well as on SIP trunks. Cisco Unified Communications Manager handles media encryption keys differently for different devices and protocols. All phones that are running SCCP get their media encryption keys from Unified Communications Manager, which secures the media encryption key downloads to phones with TLS encrypted signaling channels. Phones that are running SIP generate and store their own media encryption keys. Media encryption keys that are derived by Unified Communications Manager system securely get sent via encrypted signaling paths to gateways over IPSec-protected links for H.323 and MGCP or encrypted TLS links for SCCP and SIP. Note Devices must state upon negotiation if it can use SRTP. CUCM does not support SRTP if the device uses cached previous negotiations SDP with different devices within the same call. Security Guide for Cisco Unified Communications Manager, Release 15 and SUs 21 An Introduction to Unified CM Security Signaling Encryption