A greylist is a list that contains temporarily rejected email addresses. It’s a protection method that defends users from spam and prevents suspicious senders from sending emails. You can add certain domains or specific email addresses to your greylist to protect yourself from spam. You can also make exceptions for certain domains. For instance, you can make emails from domains like yahoo.com, gmail.com, or outlook.com, exempt from your greylist. That way, emails sent from those domains will never be on your greylist, and you’ll always receive messages from them.
A greylist is an excellent way for you to protect your email address. All you’ll have to do is enable it via your configuration settings, and you’ll be good to go. With a greylist, you won’t block the email addresses or domains that seem suspicious; you’ll just prevent them from sending you any messages.
Minimum retry interval. A minimum retry interval is the amount of time, usually expressed in minutes, before a greylisted email address goes back on the allowlist. It usually lasts 5 minutes, but you can change it if need be.
Expiration interval. An expiration interval is the amount of time, also expressed in minutes, during which an email address is kept in memory. If the email address doesn’t send another email during the expiration interval, it won’t be put back on the allowlist. The expiration interval is usually much longer than the minimum retry interval.