# What are Custom Fields in OpManager?

Custom fields are the parameters that are used to describe additional properties about an entity. They provide identifiable information about your devices, and are customizable according to your requirement. This set of custom device fields and interface fields also help the user maintain an inventory note and database of the network infrastructure. You can find this feature at **Settings > Configuration > Custom Fields**.

Learn more on how to configure Custom Fields [here](https://www.manageengine.com/network-monitoring/help/custom-fields.html).

The predefined device custom fields are as follows:

- Serial Number
- Model
- UPS
- Comments
- Building
- Department
- Floor
- Zip Code
- Postal Code
- City
- State
- Country
- Contact Name
- Telephone Number
- Cabinet
- VMWare_Tags

![Custom fields in OpManager: Device Custom Fields](https://www.manageengine.com/network-monitoring/faq/images/deviceCustomFields.JPG)

The custom field **Serial Number** is populated during device discovery using either the WMI or the SNMP protocol. To learn more about inventory listing using this custom field, refer to [this page](https://www.manageengine.com/network-monitoring/kb/serial-number-custom-fields.html).

The custom field **VMware_Tags** is available only for VMWare Hosts and VMs. The tags are user-defined names associated to various entities of the Vcenter virtual machines (VMs) and ESX hosts. These tags are retrieved from the Vsphere client and are updated periodically according to the time interval configured for Inventory update.

The predefined interface custom fields are as follows:

- Circuit ID
- Service Level Agreement (SLA)
- Contact Name
- Telephone Number
- Comments
- Local Access and Transport Area (LATA)
- Local Loop

![Custom fields in OpManager: Interface Custom Fields](https://www.manageengine.com/network-monitoring/faq/images/interfaceCustomFields.JPG)

You can choose to associate the custom fields available with the product, or create your own. A few of the fields are enabled by default, while some others have to be enabled by manual selection.

On the OpManager Enterprise Edition, you can **add** custom fields only from the Central server. This action is not permitted on the Probe servers. However, the user can **import** the custom fields created on the Central server, and **update** them on the Probe.

## Custom Fields Widget

You can find the Custom Fields widget at the bottom of every [device/interface snapshot page](https://www.manageengine.com/network-monitoring/kb/device-summary-device-snapshot.html) by default. You can use this widget to view, add, update, or delete data in the custom fields individually. For bulk update of the custom fields, you can [import values](https://www.manageengine.com/network-monitoring/help/custom-fields.html#importCF) from an external CSV file and map them to your product.

![Custom fields in OpManager: Custom fields widget on device snapshot page](https://www.manageengine.com/network-monitoring/faq/images/deviceSnapshotCustomFields.JPG)

![Custom fields in OpManager: Custom fields widget on interface snapshot page](https://www.manageengine.com/network-monitoring/faq/images/interfaceSnapshotCustomFields.JPG)

## How can you use Custom Fields?

Apart from using custom fields to just demonstrate additional data about devices and interfaces, custom fields can also be used for a wide range of critical functions. You can organize and catalogue your devices on the basis of the custom fields defined for each device. Some of the functionalities made possible by the implementation of custom fields are:

**1. Generate Reports:** You can generate custom reports like health and performance, availability and response, system reports, and so on, using custom fields as the basis of segregation. To do so, navigate to **Reports > OpManager > Advanced Report**. Select **Create New Report** and add the necessary descriptions. Now, from the "Available Column Groups", choose the custom fields you want within the report and the monitors you want the data on. You can preview the report, edit the fields, or schedule the report for a later time. Refer to [this example](https://www.manageengine.com/network-monitoring/faq/inventory-report-with-all-values.html) to learn more about how to use custom fields to generate custom reports.

![Custom fields in OpManager: Reports using custom fields](https://www.manageengine.com/network-monitoring/faq/images/customReports.JPG)

**2. Device Grouping using custom fields:** OpManager lets you bunch similar devices and interfaces into [groups](https://www.manageengine.com/network-monitoring/help/grouping.html). This can be done manually or by criteria. To group devices according to the custom fields configured in your application, navigate to **Settings > Configuration > Groups.** Select "Add" and when prompted, choose the custom fields as the requirement criteria for grouping. From the list of devices that match the criteria, select one device upon which the health of the group would depend. Check your inventory for the group containing all the devices satisfying the matching criteria.

![Custom fields in OpManager: Groups using custom fields](https://www.manageengine.com/network-monitoring/faq/images/customGroups.JPG)

**Automatic Device Grouping:** During network discovery and re-discovery, devices that belong to the criteria configured to the existing groups are automatically added to the respective group on the basis of the custom fields.