Accessing the Continuity Engine Servers

Accessing the Continuity Engine Servers

This article introduces the Neverfail Continuity Engine Management IP addressing. It allows you to manage your Neverfail Continuity Engine servers even when they are in a passive role. 

Continuity Engine employs 2 or 3 servers working together. One of the servers is active and visible to the users, and the other server (or servers) are passive and hidden from the users. The ability to access all servers for management purposes is crucial to successfully maintaining Neverfail Continuity Engine. So let's get started!
Accessing Servers

Learning objectives 

At the completion of the article you should be able to: 
  1. Identify how Neverfail Continuity Engine provides access to the server cluster.
  2. Recall exceptions to the use of management IP addressing. 
  3. Identify prerequisites for implementing management IP addressing. 


Neverfail Continuity Engine unique architecture allows a server pair or trio to present a single server presence in the public network by using a single network IP address. This single server presence provides a server management challenge where it is necessary to manage the servers remotely. But this is easily overcome. 

Management IP Addressing

To avoid IP address conflicts between Continuity Engine servers, the passive server or servers are hidden from your corporate network through the use of Windows Filtering Platform. Consequently, this prevents remote access to the passive servers via the principal network IP address. 

You can overcome this by assigning an additional IP address called the Management IP address. Since any server in the cluster may act as a passive server at any given time, you should configure all servers with fixed management IP addresses and ensure that the management IP address on each server is different.

In this way, an IP address is always visible to the network, regardless of the current role of the server, and allows continuous remote access to all servers for system management operations. 

Remote Desktop Protocol

Management IP addresses also allow access to each server by the use of Remote Desktop Protocol (RDP). With RDP properly configured and enabled on the active and passive servers, connection to all of the servers is possible by providing a remote session to manage the server. 

Console Access

With advancements in technology, direct console access is a less frequently used technique for accessing the active or passive servers. 
Console access provides direct access to the server, thereby minimizing issues related to connecting to a remote server. 
When experiencing connection problems in a LAN, this technique is preferable. When in a WAN environment, this mode of access may prove difficult, making the RDP the preferred technique. 

Special Microsoft Exchange Considerations

When configuring Neverfail Continuity Engine for use with Microsoft Exchange, it is important to remember that Microsoft Exchange Servers frequently use reverse DNS lookup for authenticating the origin of email. Since Microsoft Exchange looks for the first IP address of the sending server into the header of an SMTP packet, reverse DNS lookup may check against the management IP address, consequently failing to validate the address and inadvertently marking the email as spam. 

More information on this topic is available in the Continuity Engine help section.

DNS Registration

When implementing Management IP addressing, you must also disable automatic DNS registration on all NICs on the Primary, Secondary, and Tertiary servers by deselecting the option Register this connection in DNS (found within the advanced TCP/IP properties page for each NIC). 

If you don't deselect this option, the Management IP addresses will register themselves in DNS, and consequently will lead to DNS resolution problems within your environment.
Deselecting this box in Windows typically removes the record from your DNS server automatically. Therefore, upon deselecting this option, you may need to manually add the appropriate DNS records back into your DNS server. 

Wrap Up

This knowledge combined with knowledge gained from other Neverfail e-learning articles will assist you in enabling full management access to your Neverfail Engine servers.

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