Greylisting
Greylisting
- April 23, 2021
- Posted by: Nicola Selenu

A technique used by some Mailbox Providers and email receivers to thwart spammers. A receiving mail server using greylisting will temporarily reject any email from a sender it does not recognize. The receiver presumes that if the sender is legitimate, the originating server will most likely try again to send it later at which time the receiver will accept it. Greylisting presumes that if the sender is a spammer, they will not retry later to transmit their message.
Greylisting has disadvantages and is somewhat controversial.
Author:Nicola Selenu
Email Service Providers Handbook
The most comprehensive “Handbook of Email Service Providers“!
SPAMASSASSIN RULES
All SpamAssassin rules in one place, EXPLAINED!
SMTP COMMANDS
& REPLY CODES
All SMTP/ESMTP commands and reply codes in one place, EXPLAINED!
Free DNS Tool
Check the DNS records of your domain with our free DNS tool.
Deliverability Glossary
The most comprehensive Email Deliverability and Marketing Glossary!
Greylisting
A technique used by some Mailbox Providers and email receivers to thwart spammers. A receiving mail server using greylisting will temporarily reject any email from a sender it does not recognize. The receiver presumes that if the sender is legitimate, the originating server will most likely try again to send it later at which time the receiver will accept it. Greylisting presumes that if the sender is a spammer, they will not retry later to transmit their message.
Greylisting has disadvantages and is somewhat controversial.
Author:Nicola Selenu
Email Service Providers Handbook
The most comprehensive “Handbook of Email Service Providers“!
SPAMASSASSIN RULES
All SpamAssassin rules in one place, EXPLAINED!
SMTP COMMANDS
& REPLY CODES
All SMTP/ESMTP commands and reply codes in one place, EXPLAINED!
Free DNS Tool
Check the DNS records of your domain with our free DNS tool.
Deliverability Glossary
The most comprehensive Email Deliverability and Marketing Glossary!
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