In a Clustering over the WAN deployment, securing the ICCS (Intra-Cluster Communication Signaling) traversing the WAN can be a requirement. The IPSEC VPN Policy between nodes can be configured to secure the ICCS Traffic.To quickly verify that the IPSEC is working as expected, in the OS Administration Guide, in the Services, the ping tool has an option"Validate IPSec. If the configuration is correct. you should receive a successfull response toward the peer node.Note that only the transport mode is supported, this is because the added overhead caused by the tunnel mode.IPSEC on Cisco Unified CM can also be used to secure signaling with the MGCP or H.323 gateway.
