Disabling an alias stops mail being delivered to you. It does not delete anything. The sending server either receives a rejection or has its message silently discarded, depending on the service. The company that had the address still has it in their database, and so does anyone they sold it to — you have closed the door, not erased the record. Everything else you own keeps working, because an alias is switched off individually.
Two ways a service can handle it
This is the part worth understanding, because the difference is invisible in the interface and very visible in the outcome.
Reject (a hard bounce)
The receiving mail server refuses the message during the SMTP conversation, returning a 5xx error — a permanent failure. The sender's system is told, unambiguously, that the address does not accept mail.
What follows depends on the sender. A legitimate mailing platform treats repeated hard bounces as a signal to suppress the address, because bouncing mail damages their own deliverability reputation. In effect, the bounce does some of your unsubscribing for you. A person who emailed you by mistake gets a delivery failure notice and knows to try another route.
Accept and discard (a silent drop)
The server accepts the message normally, then throws it away. The sender sees a successful delivery and no reason to stop, so they keep sending indefinitely into nothing.
This is quieter but strictly less useful. It never tells a mailing platform to stop, and it means a genuine sender gets no warning that they didn't reach you.
Mail to a disabled alias is rejected with an SMTP 550. The sending server is told the address doesn't accept mail. We still log the attempt, so you can see who kept trying after you cut them off — which is often more revealing than the original spam.
What the sender can work out
A rejection tells the sender that the address stopped accepting mail. It doesn't tell them why, doesn't reveal your real address, and doesn't identify any of your other aliases. From their side it looks the same as an employee leaving a company.
What disabling does not do
- It doesn't delete your data. The company retains the address, your name, and whatever else you gave them.
- It doesn't reach anyone downstream. If they sold the address to twelve list brokers, those twelve still have it. They'll keep sending, and it will keep bouncing.
- It doesn't close your account. The account still exists at that service, now with a dead contact address.
- It doesn't cover your other addresses. That's the point — only that one alias stops.
If deleting the underlying record is what you're after, that's a different mechanism entirely: see data removal vs data prevention, and California's DROP platform if you're a California resident.
The one mistake to avoid
Don't disable an alias attached to an account you still need. If bank@yourdomain.com is switched off, the bank's password reset and its security alerts both bounce, and you may have a tedious support call ahead of you.
A simple rule: disable aliases for senders you're finished with, not for accounts you still use. If a service you still want starts sending too much, change the address on your account first, then disable the old alias once the new one is confirmed working.
Can you re-enable it?
With most services, yes — including Don't SPAM Me. Switching an alias back on resumes delivery. Mail that arrived while it was disabled is gone; a rejection isn't held in a queue for later.
Deleting an alias outright is different from disabling it, and on a catch-all domain a deleted address will simply be recreated the next time mail arrives for it. If you want a sender permanently cut off, keep the alias and leave it disabled rather than deleting it.
Why this is the useful part of the whole idea
Every other response to unwanted email needs somebody else to act. Unsubscribing asks the sender. Removal asks a broker. Filtering asks your provider's classifier to guess right.
Disabling an alias asks nobody. It's the one lever that's entirely yours, and it only exists if you gave that sender an address nothing else uses — which is the argument for a unique address per service.