reroute mail that fails dmarc

Question

we have read that some universities, have there dmarc or email server forwarded failed email to a sub-domain. Like bulk.domain.tld. this is for email that cant do dkim. but i dont know how this is possible.

Answer 1

Not sure what you mean, but there is no mechanism for this.
What you have read? Can you provide the link?

DMARC reports are forwarded to an email address in the DMARC DNS record:

rua=mailto:******@yourdomain.com

Note this isn't an Exchange Issue

Answer 2

It is this email that my director got

We have a DMARC policy on our primary domain (domian.edu) to mark as spam email failing to pass DMARC evaluation.
We only onboard DKIM records; the expectation is that the vendor supply us a DKIM file.
We do not entertain requests to add SPF records for vendors, as DMARC does not require both and as SPF is a limited resource.
For vendors which cannot supply a DKIM file, we have a second domain: bulkmail.domian.edu (aliased approved-senders.domian.edu) in which we have a DMARC policy which is set to deliver upon failing to pass DMARC evaluation.
We have special routing rules implemented so that email sent to @approved-sender.domian.edu addresses gets delivered to corresponding @domian.edu address.
This allows us to issue the sub-domain account/address, but no need for users to access it.
So, user wants to send email from their account: ******@domian.edu. But vendor cannot provide DKIM and achieve DMARC compliance.
We create ******@bulkmail.domian.edu (aliased ******@approved-senders.domian.edu).
Vendor sends email from: ******@approved-senders.domian.edu
Fails DMARC, but email gets delivered.
If recipient hits reply, email gets routed to ******@domian.edu
This has worked well for us for the last 4 years.