Mail software consists of a large number of cooperating pieces, described in RFC 5598. A user composes a message with a Mail User Agent (MUA), which passes it to a Mail Submission Agent (MSA), which in turn usually passes it to a sequence of Mail Transfer Agents (MTAs), which eventually hand it to a Mail Delivery Agent (MDA) to place it in the user's mail store. If the recipient user doesn't read mail on the same computer with the mail store (as is usually the case these days) POP or IMAP transfers the mail to the recipient's MUA. more
The term Email Deliverability is used to describe how well a mail flow can reach its intended recipients. This has become a cornerstone concept when discussing quality metrics in the email industry and as such, it is important to understand how to measure it. Email Deliverability is considered to be affected by a mythical metric, the reputation of the sender, which is a measure of that sender behavior over time -- and the reactions of the recipients to his messages. more
In July, several people filed attempted class action suits against Google, on the peculiar theory that Gmail was spying on its own users' mail. One of the suits was in Federal court, the other two in California state court, but the complaints were nearly identical so we assume that they're coordinated.Now we have a similar suit filed in provincial court in British Columbia, Canada. more
For many years, I have tracked spam from botnets and reported on it. I have analyzed those botnets' distribution patterns by number of IPs, number of messages per email envelope and geographical distribution. While spam from botnets is interesting, and the main source of spam, it is not the only source of spam. What about spam that originates from the MAGY sources? more
Today I released a report on 'National cyber crime and online threats reporting centres. A study into national and international cooperation'. Mitigating online threats and the subsequent enforcing of violations of laws often involves many different organisations and countries. Many countries are presently engaged in erecting national centres aimed at reporting cyber crime, spam or botnet mitigation. more
At the end of January, the DMARC (Domain-based Message Authentication, Reporting & Conformance) specification was publicly announced and resulted in widespread media coverage, blog posts and discussion. Since that time various individuals and organizations have been working on writing code for DMARC validators and report parsers. The dmarc-discuss list has been fairly active as various questions and issues have been raised and clarified. Now it is time to see how well the various implementations play together in live testing. more
US presidential candidate Mitt Romney will likely be reconsidering his email passwords after his online email account was reportedly hacked. A hacker claims to have accessed Romney's Hotmail and Dropbox accounts after guessing the answer to the Republican candidate's 'favourite pet' security question. It's suspected Romney used the same password for more than one account. more
DNS blacklists for IPv4 addresses are now nearly 15 years old, and DNSBL operators have gathered a great deal of expertise running them. Over the next decade or two mail will probably move to IPv6. How will running IPv6 DNSBLs differ from IPv4? There aren't any significant IPv6 DNSBLs yet since there isn't significant unwanted IPv6 mail traffic yet (or significant wanted traffic, for that matter), but we can make some extrapolations from the IPv4 experience. more
There has been a lot of talk about how the DNS can provide network-based security, and how DNS is in the best position to detect malware traffic before it does any harm. But what does this mean for end users? How does it make their online lives easier and more secure? DNS servers that are aware of sites that host malware, perform phishing activities (harvesting bank details, for instance) and other nefarious misbehaviors, can prevent end users from ever going to those sites. more
I opined about a year ago that DNS blacklists wouldn't work for mail that runs over IPv6 rather than IPv4. The reason is that IPv6 has such a huge range of addresses that spammers can easily send every message from a unique IP address, which means that recipient systems will fire off a unique set of DNSBL queries for every message... Now I'm much less sure this will be a problem... more
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