Packaged Contact Center Enterprise supports Symantec Endpoint Protection 12.1.
Be aware that the firewall component of Symantec Endpoint Protection 12.1, the Network Threat Protection feature, must be disabled. If the feature is enabled, both sides of a duplexed router come up in simplex mode, thus blocking communication between each side of a router. This blocking impacts all deployment types.
The problem occurs if you install Symantec Endpoint Protection 12.1 and leave the default settings. If you start services on side A and B of the router, a Symantec message pops up in the system tray indicating: The client will block traffic from IP address [side A router address] for the next 600 seconds(s). The same message is also written to the security log in client management. The Symantec Network Threat Protection traffic log indicates that a default firewall rule called “Block_all” was dynamically enabled. The result, according to the router logs, is that both sides of the router come up in simplex mode.
To resolve the issue, you must disable the Symantec firewall and restart both sides of the router. To do this, double click the Symantec icon in the system tray and select Change Settings. Then configure settings for Network Threat Protection and uncheck the Enable Firewall checkbox at the top of the Firewall tab.