If you have domains that do not send emails, you still need to lock them down so no spammers can spoof these domains to send emails. All you need is to add the following two DNS records to your domain’s DNS. First, a block-all SPF txt record: v=spf1 -all And a DMARC policy that rejects all email that fails SPF. […]
Back to the old days when everything goes through the classic SMTP, nothing gets protected. Those were the good days for any man in the middle, picking up confidential information like free gift. Not anymore with the use of TLS, StartTLS, or even better S/MIME which is suitable for your most sensitive information. Every email sent through TLS is encrypted […]
It happened lately in my office that emails sent to certain domains first got delayed and then failed with a SMTP error code 4.4.7 in the final NDR. Error code 4.4.7 usually indicates that the message in the queue has expired and usually the problem is on the receiving server. However, that is obviously not the case this time. Also […]