Enter the advanced privilege mode:
set advanced

Enable a security protocol (RSH or Telnet):
security protocol modify -application security_protocol -enabled true

Create a new management firewall policy based on the mgmt management firewall policy:
system services firewall policy clone -policy mgmt -destination-policy policy-name

Enable Telnet or RSH in the new management firewall policy:
system services firewall policy create -policy policy-name -service security_protocol -action allow -ip-list ip_address/netmask
To allow all IP addresses, you should specify -ip-list 0.0.0.0/0

Associate the new policy with the cluster management LIF:
network interface modify -vserver cluster_management_LIF -lif cluster_mgmt -firewall-policy policy-name