Updates to commercial MTAs

Last week Message Systems announced the release of Momentum 4. This high volume MTA has a large number of features that make it possible for large volume senders to manage their email and their delivery. I had the opportunity to get a preview of the new features and was quite impressed with the expanded features. Improvements that caught my eye include:

  • Real time views of delivery statistics, including opens and clicks. MessageSystems tells me some of their customers are using this to adjust campaigns on the fly.
  • Built in campaign creators. In the past Message System users have had to used other software to create their messages, now the creation is built into the MTA.
  • Template storage. Anyone inside an organization can access templates, no more awkward looking or unbranded password reset requests.

Today I also received word that Port 25 has updated the power MTA DKIM signing code to minimize DKIM replay attacks. This prevents some of the recent spam runs where senders hijack a valid reputation by taking a DKIM signed message, add extra headers and then resending it through another server.
For many applications, users can chose an open source MTA. But the commercial MTAs have a lot of features that make is so much easier for bulk senders to manage their reputations. I continue to be amazed at the features built into these appliances that make it easier for senders to comply with the challenging space that is email delivery.

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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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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 is the delete key and sometimes they’ll delete a real mail.
Every mailserver admin, whether managing a MTA for a corporation, an ISP or themselves inevitably looks at the question of false positives and false negatives. Some are more sensitive to false negatives and would rather block real mail than have to wade through a mailbox full of spam. Others are more sensitive to false positives and would rather deal with unfiltered spam than risk losing mail.
At the ISPs, many of these decisions aren’t made by one person, but the decisions are driven by the business philosophy, requirements and technology. The different consumer ISPs have different philosophies and these show in their spamfiltering.
Gmail, for instance, has a lot of faith in their ability to sort, classify and rank text. This is, after all, what Google does. Therefore, they accept most of the email delivered to Gmail users and then sort after the fact. This fits their technology, their available resources and their business philosophy. They leave as much filtering at the enduser level as they can.
Yahoo, on the other hand, chooses to filter mail at the MTA. While their spamfoldering algorithms are good, they don’t want to waste CPU and filtering effort on mail that they think may be spam. So, they choose to block heavily at the edge, going so far as to rate limit senders that they don’t know about the mail. Endusers are protected from malicious mail and senders have the ability to retry mail until it is accepted.
The same types of entries could be written about Hotmail or AOL. They could even be written about the various spam filter vendors and blocklists. Every company has their own way of doing things and their way reflects their underlying business philosophy.

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April: The month in email

April was a big month of changes in the email world, and here at Word to the Wise as we launched our new site, blog and logo.
DMARC
The big story this month has been DMARC, which started with a policy change Yahoo made on April 4 updating their DMARC policy from “report” to “reject”. We began our coverage with a brief DMARC primer to explain the basics around these policy statements and why senders are moving in this direction. We shared some example bounces due to Yahoo’s p=reject, and talked about how to fix discussion lists to work with the new Yahoo policy. We gathered some pointers to other articles worth reading on the Yahoo DMARC situation, and suggested some options for dealing with DMARC for mail intermediaries. Yahoo issued a statement about this on April 11th, explaining that it had been highly effective in reducing spoofed email. We also noted a great writeup on the situation from Christine at ReturnPath. On April 22nd, AOL also announced a DMARC p=reject record.  We talked a bit about who might be next (Gmail?) and discussed how Comcast chose to implement DMARC policies, using p=reject not for user email, but only for the domains they use to communicate directly with customers. We expect to see more discussion and policy changes over the next few weeks, so stay tuned.
Spamtraps
We wrote three posts in our continuing discussion about spamtraps. The first was in response to a webinar from the DMA and EEC, where we talked about how different kinds of traps are used in different ways, and, again, how spamtraps are just a symptom of a larger problem. Following that, we wrote more about some ongoing debate on traps as we continued to point out that each trap represents a lost opportunity for marketers to connect with customers, which is really where we hope email program managers will focus. And finally, we tried to put some myths about typo traps to rest. As I mentioned in that last post, I feel like I’m repeating myself over and over again, but I want to make sure that people get good information about how these tools are used and misused.
Security
We started the month by saying “Security has to become a bigger priority for companies” and indeed, the internet continued to see security breaches in April, including the very serious Heartbleed vulnerability in SSL. In the email world, AOL experienced a compromise, which contributed to some of the DMARC policy changes we discussed above. In a followup post, we talked about how these breaches appear to be escalating. Again, we expect to hear more about this in the next weeks and months.
Best Practices
Ending on a positive note, we had a few posts about best practices and some email basics. We started with a pointer to Al Iverson’s post on masking whois info and why not to do it. Steve wrote up a comprehensive post with everything you ever wanted to know about the From header and RFC5322. I talked about how companies ignore opt-outs, and why they shouldn’t. I shared a really good example of a third-party email message, and also talked about message volume. And finally, we talked about how and why we warm up IP addresses.
Let us know if there’s anything you’d like to hear more about in May!

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