Configuration Restrictions

Sun Cluster HA for Netscape imposes the following restrictions on Netscape Messaging Server 4.1:

• When you install Netscape Messaging Server 4.1, the listener daemons popd, smtpd, imapd, mshttpd, and stored must be configured as active, and must be configured on their default ports. If not, the startup and fault monitoring programs will perceive the daemons as inactive, and will take action based on the current configuration parameters. Further, if these two conditions are not met, the Netscape Messaging Server 4.1 instance will not start successfully. See "Fault Monitoring Behavior" for more information.

• You can configure only one Netscape Messaging Server 4.1 instance per server root, and only one server root per logical host--hence, one Netscape Messaging Server 4.1 instance per logical host.

• The Netscape Messaging Server 4.1 Multiplexor feature is not supported with Sun Cluster 2.2. Because the Multiplexor requires services located outside the server root, the Multiplexor cannot be probed or failed over by Sun Cluster HA for Netscape.

• Though Netscape Messaging Server 4.1 supports SSL-enabled listening for some of its protocols, the separate ports using SSL are not fault probed by Sun Cluster HA for Netscape. Basic restart and failover is supported, however, for any Netscape Messaging Server 4.1 instances listening on SSL-enabled ports.

• Netscape Messaging Server 4.1 supports SMTP plug-ins--shared libraries that you can install and configure to be used by Netscape Messaging Server 4.1 for customized SMTP processing. If you configure Netscape Messaging Server 4.1 to use SMTP plug-ins, then be sure to protect the shared libraries with Sun Cluster. Do this by placing the libraries on the shared disk, preferably within the Netscape Messaging Server 4.1 server root tree, or by placing the libraries on local disks on each potential master node.

• Netscape Messaging Server 4.1 supports sophisticated access control on a service-by-service basis for its TCP-based services (IMAP, POP, HTTP, and SMTP). You can enable this feature by creating filters to screen access to servers. However, if you create filters, do so with care so that you do not prevent root on any potential master from connecting to any of the Netscape Messaging Server 4.1 protocol servers. If root is prevented from connecting to any of the protocol servers, the data service probe that tests protocol service availability will fail, triggering Sun Cluster HA for Netscape to take action based on the current configuration parameters. This behavior will continue indefinitely until the filter in question is removed or the probe terminated. Make sure that root access is enabled from all nodes that are potential masters of the protocol servers.