Planning DKIM setup – what happens if “From” field is empty in ServiceNow SMTP?

[deetchigas]

I'm currently planning to set up DKIM for outbound emails in our ServiceNow instance. As part of the prep, I was reviewing our Email Account (SMTP) configuration and noticed the following:

The SMTP username is set to: support@companydomain

The "From" field is currently empty

However, emails sent from the platform appear to be coming from support@companydomain, which matches the username — not from support@instance.service-now.com, and not a default address.

I have a few questions:
Is it expected that when the From field is empty, ServiceNow uses the username as the "From" address?

Is this behavior officially documented?

Will DKIM signing be based on the actual From domain ?

If I fill in the "From" field with a domain we plan to sign for (e.g., support@companydomain), will that override the current behavior and align better with DKIM?

I want to make sure that the domain being signed matches the actual "From" address in emails — especially since we plan to publish DKIM records and request signing via ServiceNow's OOTB SMTP.

[Rachna S]

Hi,

Did you manage to find answers yet ? We're going through the same thing and I'm not sure where to update the 'from' address for emails sent to only a certain mailboxes from ServiceNow. 

[deetchigas]

Hi Rachna,

Yes, I’ve reviewed the official documentation and successfully implemented DKIM, it’s working as expected. As part of the DKIM and email reprovisioning setup, the "From" address will be automatically updated.

Could you please clarify your question? I’ll be happy to assist further once I understand it better.

[Rachna S]

Thank you for your response. In our case however, even though re-provisioning was done it did not update the 'from' address anywhere.

[deetchigas]

So , now it uses your username to send the emails? . I think you can update From field 
with your custom email . I hope below explanation helps. If not i would suggest you to contact servicenow support
Here is the link :
https://www.servicenow.com/docs/bundle/yokohama-platform-administration/page/administer/notification...
"(SMTP only) The From address used for notifications sent with this account. This address takes precedence over the User name field. If nothing is present in this field, the User name is used as the return address for notifications sent from the instance."