Top Deliverability’s Blog
Spam Resource: DELIVTERMS: Greylisting
- May 12, 2022
- Posted by: Top Deliverability
- Category: Industry News Spam Resource
Al Iverson just posted another engaging article on Spam Resource:
DELIVTERMS: The weekly series here on Spam Resource that defines deliverability terminology. Today, I’m going to talk about Greylisting.What is it? Greylisting is where an ISP or mailbox provider configures their mail server to temporarily delay incoming email. Usually not long — perhaps for only 60 seconds to a few minutes.How? Mail servers that support this have a setting where they track server connections. If it’s the first time a certain server or domain connects to them, they defer (temporarily reject) that connection or address with a 4xx temporary failure. This invites the sending server to try again later. Most sending mail servers have a “retry interval” setting that governs how long until they retry. In some cases, it’s 15 minutes, in other cases, a few hours. This can usually be configured by the administrator of the sending MTA.Why? It’s a form of spam filtering. It is done to stop…
More here: DELIVTERMS: Greylisting
Leave a Reply Cancel reply
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!
- Term: Spam
- Term: Deliverability
- Term: Greylisting
- Term: Internet Service Provider (ISP)
- Term: Mailbox Provider (MBP)
- Term: Sending MTA
- Term: Spam Placement
- Term: Email Service Provider (ESP)
- Term: SpamAssassin
- Term: Simple Mail Transfer Protocol (SMTP)
- Term: Accelerated Mobile Pages (AMP)
- Term: Extended Simple Mail Transfer Protocol (ESMTP)
- Term: Domain Name System (DNS)