This Knowledgebase article provides information about configuring the Neverfail Channel and Principal (Public) connections to use the same subnet.
The following information applies to both Local Area Networks (LAN) and Wide Area Networks (WAN) and when deployed as either a Pair or a Trio.
Note: Neverfail recommends at least two physical NICs on each server to provide hardware redundancy and prevent a single point of failure.
When configuring Principal (Public) and Neverfail Channel connections, the following recommendations should be followed:
Neverfail Channel Considerations
- If the IP addresses at each end of a Neverfail Channel connection are in a different subnet from each other, you must add static routes as described in Knowledgebase article #466 - How to Create a Static Route for the Neverfail Channel Connection in a WAN Environment regardless of the Principal (Public) IP addresses. When deployed in a Trio, the same rule applies for each Neverfail Channel connection.
- If the subnet used for a Neverfail Channel IP address is used solely for Neverfail Channel addressing, then the subnet mask may be relaxed to 255.255.255.0
- If the subnet used for Neverfail Channel IP addresses is used for any other traffic, then the subnet mask (as mentioned in Knowledgebase article #466) must be 255.255.255.255
Dedicated (Separate) NICs in Dedicated (Separate) Subnets
When the Principal (Public) connection and the Neverfail Channel connection(s) are on separate dedicated NICs and separate dedicated subnets, then the only requirement is to ensure that channel traffic is able to be routed across the Neverfail Channel. Rules 1a and 1b above should be considered and static routes added if required.
Dedicated (Separate) NICs and Same Subnet
If the Principal (Public) IP address and Neverfail Channel IP address(es) are configured on dedicated (separate) NICs, but in the same subnet, then the Neverfail Channel IP address(es) need to have a subnet mask of 255.255.255.255 as described in item 1 above. Static routes as per Knowledgebase article #466 will always be required, even if the IP addresses at both ends of the channel link are on the same subnet.
Same NIC and separate (dedicated) Subnet
Note: This applies to Windows Server 2008 and later, and is not supported on Windows Server 2003
If the Principal (Public) IP address and Neverfail Channel IP addresses are configured on the same NIC but on different subnets, the rules in item 1 above apply.
Same NIC and Same Subnet
This configuration is not currently supported.
Management IP Addressing
The Management IP address, if any must not permit access to any domain controllers on the network.
The Management IP address should be configured on a unique subnet, different from the subnet(s) used for the Principal (Public) IP address and Neverfail Channel IP address.
Note: When Principal (Public) and Neverfail Channel IP addresses on a server are on different NICs and different subnets, then the existing implementations will work.
Neverfail Heartbeat All Versions
Knowledgebase article #466 - How to Create a Static Route for the Neverfail Channel Connection in a WAN Environment