September 2014: The Month in Email

September was another busy month for us, but Steve stepped up and wrote a number of really interesting posts on email history, cryptography, and current technical issues in the email landscape.
We started the month with a look at the various RFCs that served as the technical specifications for developing message transfer protocols in the 1970s. It’s really fascinating to look at the evolution of these tools we use every day 40 years later. We followed up with a second post on the origins of network email, which is a great primer (or refresher) on the early days of email.
Steve’s four-part series on cryptography and email started with an in-depth look at how the industry is evolving with respect to encryption and privacy issues. He then introduced us to Alice and Bob (or reintroduced those of us who have been following the adventures of the first couple of cryptography), and described symmetric-key and public-key encryption. His next post described message signing, and how DKIM is used to manage this. He finished up the series with a post on PGP keys.
In industry news: Spamcop is shutting down its email service. There shouldn’t be any major impact on senders, but the post has some specific notes on DMARC implications. We also noted an interesting mail routing suggestion on Twitter, and wrote a post on using Mail.app for this.
In other DMARC news, we wrote about DMARC and report size limits, which might be useful information, depending on your configuration. We also launched a new DMARC tool to help senders understand who is publishing DMARC. Let us know what you think and if you’re finding it useful.
We couldn’t let a month go by without mentioning filters. We looked at a sector we don’t usually discuss, corporate filtering, and went in-depth on a much-misunderstood topic, content filtering.
Finally, Laura offered a webinar on a favorite topic, deliverability, in conjunction with the AMA and Message Systems. If you missed it, you can watch the recorded version here, or just take a peek at some of the reaction via Twitter.

Related Posts

Alice and Bob and PGP Keys

Last week Alice and Bob showed how to cryptographically sign messages so that the recipient can be sure that the message came from the purported sender and hasn’t been forged by a third party. They can only do that if they can securely retrieve the senders public key – which means they need to retrieve it from the actual sender, rather than an impostor, and be sure it’s not tampered with en route. How does this work in practice?
If I want to send someone an encrypted email, or I want to verify that a signed email I received from them is valid, I need a copy of their public key (almost certainly their PGP key, in practice). Perhaps I retrieve it from their website, or from a copy they’ve sent me in the past, or even from a public keyserver. Depending on how I retrieved the key, and how confident I need to be about the key ownership, I might want to double check that the key belongs to who I think it does. I can check that using the fingerprint of the key.
A key fingerprint looks like this:

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May 2014: The month in email

It’s been a busy and exciting month for us here.
Laura finished a multi-year project with M3AAWG, the Messaging, Malware and Mobile Anti-Abuse Working Group (look for the results to be published later this year) and continued working with clients on interesting delivery challenges and program opportunities. Steve focused on development on the next version release of Abacus, our flagship abuse desk tool, which will also be available later this year.
And as always, we had things to say about email.
The World of Spam and Email Best Practices
We started the month with a bit of a meta-discussion on senders’ fears of being labeled spammers, and reiterated what we always say: sending mail that some people don’t want doesn’t make you evil, but it is an opportunity to revisit your email programs and see if there are opportunities to better align your goals with the needs of people on your email lists. We outlined how we’ve seen people come around to this position after hitting spamtraps. That said, sometimes it is just evil. And it’s still much the same evil it’s been for over a decade.
We also wrote a post about reputation, which is something we get asked about quite frequently. We have more resources on the topic over at the WiseWords section of our site.
Gmail, Gmail, Gmail
Our friends over at Litmus estimate Gmail market share at 12%, which seems pretty consistent with the percentage of blog posts we devote to the topic, yes? We had a discussion of Campaign Monitor’s great Gmail interview, and offered some thoughts on why we continue to encourage clients to focus on engagement and relevance in developing their email programs. We also wrote a post about how Gmail uses filters, which is important for senders to understand as they create campaigns.
SMTP and TLS
Steve wrote extensively this month about the technical aspects of delivery and message security. This “cheat sheet” on SMTP rejections is extremely useful for troubleshooting – bookmark it for the next time you’re scratching your head trying to figure out what went wrong.
He also wrote a detailed explanation of how TLS encryption works with SMTP to protect email in transit, and followed that with additional information on message security throughout the life of the message. This is a great set of posts to explore if you’re thinking about security and want to understand potential vulnerabilities.
DKIM
Steve also wrote a series of posts about working with DKIM (DomainKeys Identified Mail), the specification for signing messages to identify and claim responsibility for messages. He started with a detailed explanation of DKIM Replay Attacks, which happens when valid email is forwarded or otherwise compromised by spammers, phishers or attackers. Though the DKIM signature persists (by design) through a forward, the DKIM specification restricts an attacker’s ability to modify the message itself. Steve’s post describes how senders can optimize their systems to further restrict these attacks. Another way that attackers attempt to get around DKIM restrictions is by injecting additional headers into the message, which can hijack a legitimately signed message. If you’re concerned about these sort of attacks (and we believe you should be), it’s worth learning more about DKIM Key Rotation to help manage this. (Also of note: we have some free DKIM management tools available in the WiseTools section of our site.)
As always, we’re eager to hear from you if there are topics you’d like us to cover in June.

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June 2014: The month in email

Each month, we like to focus on a core email feature or function and present an overview for people looking to learn more. This month, we addressed authentication with SPF.
We also talked about feedback mechanisms, and the importance for senders to participate in FBL processes.
In our ongoing discussions about spam filters, we took a look at the state of our own inboxes and lamented the challenge spam we get from Spamarrest. We also pointed out a post from Cloudmark where they reiterate much of what we’ve been saying about filters: there’s no secret sauce, just a continuing series of efforts to make sure recipients get only the mail they want and expect to receive. We also looked at a grey area in the realm of wanted and expected mail: role accounts (such as “marketing@companyname.com”) and how ESPs handle them.
As always, getting into the Gmail inbox is a big priority for our clients and other senders. We talked a bit about this here, and a bit more about the ever-changing world of filters here.
On the subject of list management, we wrote about the state of affiliate mailers and the heightened delivery challenges they face getting in the inbox. We got our usual quota of spam, and a call from a marketer who had purchased our names on a list. You can imagine how effective that was for them.
And in a not-at-all-surprising development, spammers have started to employ DMARC workarounds. We highlighted some of the Yahoo-specific issues in a post that raises more questions.
We also saw some things we quite liked in June. In the Best Practices Hall of Fame, we gave props to this privacy policy change notification and to our bank’s ATM receipts.
We also reviewed some interesting new and updated technology in the commercial MTA space, and were happy to share those findings.

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