Error Message Indicates Unknown Host

Problem:

An error containing the following text appears:

Unknown Host. Please check the values and try again.

This error indicates that the Enterprise Manager is unable to connect to a managed server Server that is managed by the Enterprise Manager application..

This error may appear in the System logs or on these Enterprise Manager screens:

• System Management, Enterprise, Settings

• System Management Module that allows performing suite-wide system management activities from a single, Web-based application, the Enterprise Manager., Enterprise, Configuration Status

• System Monitoring, System Monitor, Alarm Status

Solution:

A managed server’s host name is entered in the Server Name field on the System Management, Enterprise, Settings screen for the managed server.

The Unknown Host error often indicates that the Domain Name System (DNS) does not have an entry for the host name entered the Settings screen.

To address this problem, first ping the host name that is specified on the managed server’s Settings tab. If the ping fails, the problem is likely caused by one of these two issues:

• An incorrect host name is specified in the managed server’s Settings screen

• A firewall is blocking the connection to the host name

To fix this problem, do one of the following:

• Specify the correct host name for the managed server in the Server Name field on the System Management, Enterprise, Settings screen for the managed server. If necessary, contact The entire communication experience for a customer, from beginning to end. the enterprise’s IT department to determine the correct host name for the server.

• Configure any firewall between the Enterprise Manager application and the managed server to allow HTTP connections between the Enterprise Manager and the managed server. The Enterprise Manager communicates with a managed server using HTTP on default port 80 (or HTTPS port 443).