Symantec Encryption Desktop clients cannot connect to the Symantec Encryption Management Server when one server is unavailable, even though there are two or more Encryption Management Servers in a cluster.
Web Email Protection users may not see all their new messages when they log in.
By default, the Encryption Desktop installation file downloaded from Encryption Management Server contains the FQDN (fully qualified domain name) of the server from which the installation file is downloaded.
During the enrollment process, the client is bound to a single Encryption Management Server. If that server is unavailable, the client will not be able to connect.
For Web Email Protection, a user may be directed to a cluster member that has not received the replicated data yet.
Two or more Encryption Management Servers in a cluster.
In a clustered environment, a FQDN that can resolve to more than one Encryption Management Server is required in order to provide fail over for clients. For example, the FQDN might be keys.example.com.
This FQDN is specified in the Symantec Encryption Server text box in the Consumers / Groups / Download client page of the admin console.
Because the clients connect to the server over a secure channel, each Encryption Management Server in the cluster requires an SSL certificate with a Common Name that matches the FQDN to which the clients connect. For example, the certificate Common Name might be keys.example.com.
Symantec recommends that cluster replication should be configured to use network Interface 1 and that each interface used for clustering should have a unique SSL certificate. See article 154069 for further information. For example, in a three member cluster consisting of sems1.example.com, sems2.example.com and sems3.example.com, Interface 1 of sems1 would have a certificate with the Common Name sems1.example.com, Interface 1 of sems2 would have a certificate with the Common Name sems2.example.com and Interface 1 of sems3 would have a certificate with the Common Name sems3.example.com.
Since Interface 1 is used for replication and each server has a unique certificate assigned to Interface 1, client communications need to be handled by a different Interface, usually Interface 2.. The same SSL certificate needs to be assigned to all servers that handle client traffic because the clients need to trust it. For example, all servers might have the certificate for keys.example.com assigned to Interface 2.
Round Robin for load balancing is not supported. See article 162371 for further details. A single Encryption Management Server can easily service tens of thousands of clients so the main advantage to having a cluster of Encryption Management Servers is high availability and not load distribution.
DNS can be used to point the FQDN that Encryption Desktop clients use to a specific Encryption Management Server. If that server becomes unavailable, DNS can be manually updated to point the FQDN to another server in the cluster. For example, keys.example.com might point to Interface 2 of sems1 which has an IP of 10.10.10.11. If sems1 is unreachable, the DNS entry might be changed to point to Interface 2 of sems2 which has an IP of 10.10.10.12.
As an alternative to DNS, a load balancer can be used. However, the load balancer must not be configured to use Round Robin, even though it is the default for most load balancers. Depending on the specific load balancer, the following methods can be used in order of preference:
In all cases, the so-called "sticky bit" or "persistence" should be set so that clients do not connect to a different server during their session.