Dell NetWorker 19.9 Administration Guide

Verifying correct hosts file resolution

The operating system provides NetWorker with the first entry in the hosts file that matches the name resolution requirement. Additional instances of an IP address, FQDN, or shortname that appear in the hosts file for a host are ignored when NetWorker tries to resolve names.

When you create or modify the hosts file, ensure that you:

• Specify each hostname or IP address only once.
• Specify each FQDN and alias for a host on the same line as the IP address. For example:

  IP address Canonical name FQDN alias alias...

• Specify the IPv6 loopback interface (::1) with the localhost on Linux and UNIX, when the operating system configures the IPv6 loopback interface. For example:

  ::1 localhost6
  127.0.0.1 localhost

  NOTE:The IPv6 loopback entry must remain in the hosts file when the host exists in a pure IPv4, pure IPv6, or dual stack configuration to ensure that localhost is resolvable. If IPv6 is enabled and ::1(IPv6 localhost) cannot be resolved, the following error message is displayed:

  Ensure that host 'hostname' is resolvable in the IPV6 enabled environment.