When VIP addresses are assigned to CommuniGate Pro Domains, you may want to configure your CommuniGate Pro Modules to initiate outgoing TCP connections using these VIP addresses as source IP addresses. If you do so, the response TCP packets will be directed to the Load Balancer, which should be configured to direct them to the proper Cluster Member - to the CommuniGate Pro Server that has initiated the TCP connection.
For each Cluster Member that can initiate TCP connections (usually the frontend servers), select a port range for outgoing connections. These ranges should not intersect. For example, select the port range 33000-33999 for the first Cluster Member, 34000-34999 for the second Cluster Member, etc.
Make sure that the server OS is configured so that the selected port range is outside of the OS "ephemeral port" range. For example, the following command can be used to check the Linux OS "ephemeral port" range:
[prompt]# cat /proc/sys/net/ipv4/ip_local_port_range 32768 61000 [prompt]#
and the following command can be used to change the Linux OS "ephemeral port" range:
[prompt]# echo "50000 61000" >/proc/sys/net/ipv4/ip_local_port_range cat /proc/sys/net/ipv4/ip_local_port_range 50000 61000 [prompt]#
To make these changes permanent, add the following line to the Linux /etc/sysctl.conf file:
net.ipv4.ip_local_port_range = 50000 61000
For each of these Cluster members, open the Network settings in the WebAdmin Settings realm, and specify the selected TCP port range. Disable the Use for Media Proxy only option to make the CommuniGate Pro Server software use the selected port range for all outgoing TCP connections with a predefined source address.
Configure the Load Balancer: all packets coming to VIP address(es) and to any port in the selected port range should be directed to the corresponding Cluster Member.