The Postmastery Blog: Insights, Tools & Best Practices for Email Deliverability
DKIM recipe for PowerMTA
2010/01/01 by Maarten Oelering.
DomainKeys, and it’s successor DKIM, are important email authentication techniques. Based on cryptography, they are more secure than SPF and Sender ID. With DomainKeys/DKIM the integrity of the content is also protected and authentication does not break when emails are being forwarded. DomainKeys/DKIM is used by large webmail providers such as Google, Yahoo and AOL. […]
Hotmail throttling and PowerMTA
2010/01/01 by Maarten Oelering.
Windows Live Hotmail is famous for throttling senders based on their IP reputation. The following two SMTP errors might be familiar: 421 PR(ct1) The mail server IP connecting to Windows Live Hotmail server has exceeded the connection limit allowed. If you are not an email/network admin please contact your E-mail/Internet Service Provider for help. For […]