Catch-all is the type of email address that causes the most confusion for our clients and handling them properly requires an understanding of what they are and how they work.
The right strategy depends on the specifics of your situation, such as your data collection practices, the goals of your campaign, and how you send your email campaigns.
But don’t worry! This article will introduce you to catch-all servers and the associated risks, allowing you to make the right decisions for your business.
What is a catch-all email server?
A catch-all email server is also referred to as an “accept all” server, which should help you understand how it functions:
A catch-all is a mail server configured to accept all emails sent to the domain, regardless of whether or not the specified mailbox exists.
Office 365 mail servers are mostly catch-all, therefore unverifiable by other services. For instance, the RampedUp mail server is Office 365 and is set up as catch-all, so any email address at the RampedUp.io domain would be accepted, such as
donald.duck@RampedUp.io, mickeymouse@RampedUp.io or who.email.address@RampedUp.io.
Why do catch-all emails exist?
Initially, webmasters used catch-all servers to prevent emails from being lost. Erroneous addresses were redirected to a generic “catch-all” mailbox. This mailbox could be reviewed periodically to ensure that no important messages went missing.
Catch-all servers make it easier for spammers to bombard a domain with unsolicited messages. For this reason, catch-all mailboxes today tend to be overloaded with spam, which can make them functionally useless and prone to be over quota.
The risks of catch-all emails
There are a few ways that catch-all servers can cause you problems:
- Increased Bounce Rate – Unpredictable bounces are the biggest risk to your sender reputation and the main reason to be extremely cautious.
- Some servers may automatically bounce (hard bounce) messages after initially accepting them.
- Catch-all mailboxes frequently go over their quotas, resulting in additional bounces.
- Unopened Messages – Catch-all email folders may not be monitored regularly and can even be configured to automatically delete messages to non-existent mailboxes. Expect a lower than average open rate.
- Email Service Providers – Most email service providers have very low tolerance for bounces; so if you use an ESP be very cautious with catch-all emails, especially if they are from an unknown source, to avoid having your account suspended. Our Email Validation Statuses
- Spam Trap– These emails are unsafe to send in bulk and are either a known complainer or not associated with a real person.
- Valid– These emails are associated with a real person and have been confirmed by the recipient’s email server.
- Invalid– These emails are either malformed, the domain doesn’t accept email, or the recipient’s email server reports the email address is bad.
- Catch All– These email addresses cannot be validated, just the domain, because the recipient’s server returns no credible deliverability information.
- Deterministic – These are Catch All email addresses but we add a layer of confidence that the email was once delivered successfully.
- Unknown – Not enough information was given to validate this email address. It could be the server wasn’t taking requests or taking too long to respond.