The Icmp heartbeat may display a State of "UNKNOWN", although the ClusterAddress for the remote cluster has been configured.

# hahb-display
#HB          Attribute    Scope          Value
Icmp        AYAInterval   global        60
Icmp        AYARetryLimit global        3
Icmp        AYATimeout    global        300
Icmp        AgentState    global        ON
...
Icmp        StartTimeout  global        300
Icmp        State        clus_remote    UNKNOWN   <<<<<<<
Icmp        StopTimeout   global        300

The Remote Cluster's IP address can be successfully pinged.

#ping  
 is alive

The solution is to place the remote cluster's ClusterAddress IP and hostname in DNS or in the local /etc/hosts file:

After putting this information in the hosts file, the Icmp heartbeat has the proper ALIVE state:

#hahb-display
#HB          Attribute    Scope          Value
Icmp        AYAInterval   global        60
Icmp        AYARetryLimit global        3
Icmp        AYATimeout    global        300
Icmp        AgentState    global        ON
...
Icmp        StartTimeout  global        300
Icmp        State        clus_remote    ALIVE   <<<<<<
Icmp        StopTimeout   global         300