Tag: Technical

What is Two Factor Authentication?

Two factor authentication, or the snappy acronym 2FA, is something that you’re going to be hearing a lot about over the next year or so, both for use by ESP employees (in an attempt to reduce the risks of data theft) and by ESP customers (attempting to reduce the chance of an account being misused […]

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Real. Or. Phish?

After Epsilon lost a bunch of customer lists last week, I’ve been keeping an eye open to see if any of the vendors I work with had any of my email addresses stolen – not least because it’ll be interesting to see where this data ends up. Yesterday I got mail from Marriott, telling me […]


Multipart MIME cheat sheet

I’ve had a couple of people ask me about MIME structure recently, especially how you create multipart messages, when you should use them and which variant of multipart you use for different things. (And I’m working on a MIME parser / generator for Abacus at the moment, so it’s all fresh in my mind) So […]

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Yes, we have no IP addresses, we have no addresses today

We’ve just about run out of the Internet equivalent of a natural resource – IP addresses. ICANN allocated the last couple of blocks of general usage IPv4 addresses to APNIC earlier today. There are just five usable blocks of addresses left, and they’re reserved by IANA policy for the final phase of IPv4 exhaustion, one […]


Clicktracking 2: Electric Boogaloo

A week or so back I talked about clicktracking links, and how to put them together to avoid abuse and blocking issues. Since then I’ve come across another issue with click tracking links that’s not terribly obvious, and that you’re not that likely to come across, but if you do get hit by it could […]

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Clicktracking link abuse

If you use redirection links in the emails you send out, where a click on the link goes to your server – so you can record that someone clicked – before redirecting to the real destination, then you’ve probably already thought about how they can be abused. Redirection links are simple in concept – you […]


Abuse Reporting Format

J.D. has a great post digging into ARF, the abuse reporting format used by most feedback loops. If you’re interested in following along, you might find this annotated example ARF report handy.

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Poor delivery can't be fixed with technical perfection

There are a number of different things delivery experts can do help senders improve their own delivery. Yes, I said it: senders are responsible for their delivery. ESPs, delivery consultants and deliverability experts can’t fix delivery for senders, they can only advise. In my own work with clients, I usually start with making sure all […]


The view from a blacklist operator

We run top-level DNS servers for several blacklists including the CBL, the blacklist of infected machines that the SpamHaus XBL is based on. We don’t run the CBL blacklist itself (so we aren’t the right people to contact about a CBL listing) we just run some of the DNS servers – but that means that […]

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How to disable a domain

Sometimes you might want to make it clear that a domain isn’t valid for email. Perhaps it’s a domain or subdomain that’s just used for infrastructure, perhaps it’s a brand-specific domain you’re only using for a website. Or perhaps you’re a target for phishing and you’ve acquired some lookalike domains, either pre-emptively or after enforcement […]

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