If your Greenplum Database cluster employs Kerberos user authentication, your client host must be configured to access Greenplum with Kerberos. Refer to the following documentation for instructions on configuring Kerberos authentication on a client system:

• UNIX client hosts - Configuring Kerberos for Linux Clients
• Windows client hosts - Configuring Kerberos for Windows Clients

If your Greenplum Database cluster is not using Kerberos for user authentication, then this configuration is not required.