ServiceNow Emails Marked as Junk Due to X-ServiceNow-Generated Header: Loop Prevention Clarification

[SANKARRAMR]

Hi everyone,

I’m validating a scenario between two ServiceNow instances (Instance A and Instance B).

Current Issue:

• Emails sent from Instance A to Instance B are going to Junk

• This is due to the header: X-ServiceNow-Generated: true

• Instance B is filtering these emails to prevent potential mail loops

Requirement:

• Instance B should receive emails and create cases

• Instance A should not create any tickets or cause a loop

Validation Done on Instance A:

Case Creation:

• Reviewed all inbound email actions

  • No configuration exists to process emails from Instance B

• Tested via email reprocessing

  • No ticket or case created

Case Update Conditions:

• Sender must exist as a user in Instance A

• Sender must have required access to the case

Additional Finding:

• Identified one custom auto-reply flow being triggered

Mitigation:

• Auto-reply flow can be updated to exclude Instance B domain

• This will prevent any response being sent back

Understanding (Need Validation):

• If Instance B allows emails from Instance A

• And Instance A does not process inbound emails into tickets

• And auto-reply is disabled for Instance B

• Then:

  • Instance B can create cases

  • Instance A will remain passive and not participate in a loop

Additional Clarifications:

• If Instance B sends an auto-generated response:

  • It will also contain X-ServiceNow-Generated: true

  • Will Instance A handle this safely by default, or could it trigger unintended behavior?

• If Instance A uses a custom SMTP/email account:

  • Will X-ServiceNow-Generated: true still be present?

Goal:

• Ensure Instance B can process emails and create cases

• Ensure Instance A does not create tickets or contribute to any loop

Any inputs or corrections would be helpful.
Thanks!