---
title: Blocking and replacing aliases
updated: 2026-10-15
summary: Shut off a leaked address, or swap it for a fresh one.
section: Aliases
order: 2
---

## Blocking a sender

Block a single sender's domain on an alias to stop their mail without touching anyone else's. You can't block the company the alias was given to. Block the whole alias instead.

## Blocking an alias

**Block all mail** shuts an alias off. Senders aren't told: their mail is accepted and thrown away.

Yellowbird keeps only the sender, subject and date of the last 50 emails, so you can see what you're missing. Older ones are counted but not kept. Choose **Unblock** to start getting mail again.

## Replacing an alias

**Replace alias** makes a new address with the same name and settings, and blocks the old one straight away. Update your address with the company afterwards, because mail to the old alias won't reach you.

Blocked aliases don't count towards your alias limit.

[Custom aliases](/help/aliases#custom-aliases) can't be blocked or replaced. Delete one instead.

## Deleting an alias

**Delete** removes an alias for good, along with its list of senders, blocked senders and withheld mail. Mail sent to it afterwards bounces, and the address is never given out again. Mail it already received stays in your mailbox.

Blocking is usually the better choice: it keeps the alias's history and can be undone. Delete an alias when you want it gone from your list.