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Email Bounces: Complete Guide to Handling Bounce Messages
Learn about email bounces and how to handle them. Understand hard bounces vs soft bounces, bounce handling best practices, and how to reduce bounce r...
Greylisting
Greylisting is an anti-spam technique where a receiving server temporarily rejects emails from unknown senders to test if they are legitimate.
Greylisting is a method used by email servers to filter out spam. When a server receives an email from a sender it doesn't recognize (based on IP address and sender address), it temporarily rejects the message with a "try again later" error (a 4xx deferral).
Legitimate email servers (MTAs) are built to retry sending messages after a delay, so the email will eventually get through. Spammers, however, often use "fire-and-forget" scripts that do not retry, meaning their spam gets blocked.
While effective at stopping some spam, greylisting causes a slight delay in email delivery for new senders. Once a sender successfully passes the retry test, they are usually whitelisted for future emails.
Related Terms
Spam
Spam is any email sent to someone without their clear permission or after they have lost interest in hearing from you. It is email that feels unwanted or irrelevant to the person receiving it.
Learn more →Shared Server(Shared IP)
A shared server is an email server and IP address that many companies use to send their emails. Your messages go out from the same place as other senders, so you share the same reputation.
Learn more →List(Audience)
Your email list is the group of people who have asked to hear from you by email. It is an audience you own and can contact any time without relying on ads or social platforms.
Learn more →Spam Trap(Honeypot Address)
A spam trap is an email address used by inbox providers to spot bad or careless senders. Hitting one damages your sender reputation and makes it more likely your emails go to spam.
Learn more →