A few weeks ago I wrote a blog post focusing on one small part of bounce handling. Today I want to talk about delivery failures that aren’t bounces. This is really the biggest issue for companies who have written their own bulk sending servers. Modern bulk MTA appliances and ESPs correctly handle these types of bounces. However, when you’re troubleshooting it’s important to know...
About that DMARC "exploit"
A security researcher has identified a rendering flaw that allows for “perfect” phishing emails. From his website: Mailsploit is a collection of bugs in email clients that allow effective sender spoofing and code injection attacks. The spoofing is not detected by Mail Transfer Agents (MTA) aka email servers, therefore circumventing spoofing protection mechanisms such as DMARC...
You can't technical yourself out of delivery problems
In many cases these days, many more cases than a lot of senders want to admit, delivery problems at the big ISPs are a result of sending mail recipients just don’t care about. The reason your mail is going to bulk? It’s not because you have minor problems in your headers. It’s not because you have some formatting issues. The reason is because your recipients just don’t...
Why do ISPs do that?
One of the most common things I hear is “but why does the ISP do it that way?” The generic answer for that question is: because it works for them and meets their needs. Anyone designing a mail system has to implement some sort of spam filtering and will have to accept the potential for lost mail. Even the those recipients who runs no software filtering may lose mail. Their spamfilter...