How to Perform Lookups to Identify the Resources in PAS

When system resources are registered or discovered in PAS, the value for the DNS Name/IP Address field is updated with the IP address, DNS name or FQDN.

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There are no independent fields in PAS to store each separately. ServiceNow usually fetches the details of resources using IP addresses to perform a test credential and a Discovery.

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When a request containing an IP address is raised from ServiceNow, a reverse DNS or FQDN lookup is required to find the matching system stored in PAS.

Lookup Conditions

The user is required to set parameters in the configuration file to allow certain lookups. For more details, refer to the following:

  • use_reverse_dns_lookup: true/false (default false)
  • use_fqdn_lookup: true/false (default false)
  • look_up_order : “IP”, “DNS”, “FQDN” (default “IP”)

With the configuration example above, the plugin will do the following:

  • Look up the credentials using the requested value (for an IP, DNS or FQDN).
  • Look up the credentials using the IP address.
  • Look up the credentials using the results from a reverse DNS look up.
  • Look up the credentials using the results from a FQDN look up.
  • Or, a failure message will display.

If the results are successful, no further searches are needed.

Changing the lookup order or removing options will change the above logic accordingly.

The option from the lookup order will be ignored if the corresponding lookup parameter (use _reverse_dns_lookup or use_fqdn_lookup) is set to false.

This assumes that the MID Server plugin has a valid IP address and the IP address matches one of the IP addresses on the current machine.

If the IP address is not reachable from the MID Server, the DNS and FQDN lookup will fail and the search will be performed with the requested IP address.

If none of the parameters are defined in the configuration, no lookups will be performed and the value (IP, DNS Name, or FQDN) requested by the ServiceNow instance will be searched in the Server Suite. For example, if the ServiceNow request contains an IP address, then only that IP address will be searched in Server Suite.