I’m repeating the presentation I gave at M3AAWG in London for the Certified Senders Alliance.It’s all about how to send an email by hand, and how knowing the mechanics of how an email is sent can help us diagnose email delivery issues.We’re starting in about five hours from when I post this.Register at https://register.gotowebinar.com/register/2268789893122531343
If you want to learn more about SMTP response codes and error messages, here’s a couple of resources you’ll want to check out and bookmark for future reference. First, here’s John Porrini from SocketLabs: 21 SMTP Response Codes That You Need To Know.And after you’ve checked that out, you’ll want to bookmark the SMTP FIELD MANUAL: A collection of raw SMTP error codes spotted in the wild from Postmark. Very useful to try to understand what kind of rejects (bounces) certain mailbox providers will send back and sometimes it has come in handy when I can’t access to a client’s actual bounce message, so I can review what common ones that particular mailbox provider sends, and develop a thoery of what might have happened, based on that.
Need a fake SMTP server for testing? Chadwan Pawar of PostBox Services suggests Mailhog. It’s an open source SMTP server that captures all mail and gives you a visual dashboard showing you what was received. Much fancier than /dev/null (but that can come in handy sometimes, too).Read more about it over on PostBoxServices and here’s a link to the Mailhog project on Github.