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Asking for the impossible: SLAs

11 May 2010

Just a few days ago, I wrote that I cannot guarantee that my intervention will remove you from a DNSBL. Why? because I won’t agree to terms that will bind me to making someone do something.

I figured I would follow that up by looking at some contractual terms that your mail consultant and/or ESP will avoid. I want to examine the delivery service level agreement (SLA) today. A delivery SLA is a contractual term that states that the ESP will guarantee that some percentage of mail will be delivered to recipients. It takes its genesis from the uptime SLAs that ISPs and other providers regularly give to customers doing “mission-critical” things that require that their machines be online and accessible.

Yes, your ESP knows that your ISP is willing to guarantee you 99.9999999999999% uptime. Often, though, companies think they can get an ESP to guarantee that a tremendous percentage of their messages will be delivered. But, remember that your ISP does not guarantee that you can reach a particular website 99.9999999999999% only that their equipment will be up so that you can try. The reasons you might not be able to reach a website include lots of things the ISP has no control over, like the website’s system or ISP being down. Similarly, ESPs can only tell you they will have their systems up to attempt, and some do that.

Read moreThe Spock Trap

However, an ESP cannot tell you they will guarantee a certain percentage of emails will be delivered. There are too many other things involved to make that kind of promise. Things like:

  • The receiving mail server could be broken and not receive mail from anyone.
  • An administrator could have a typo on a block/filter string.
  • An undersea cable could have broken, making it impossible for the ESP’s mail server to reach the recipient’s servers on the other side of the ocean.

…And, well, you get the picture. But, perhaps the most important reason is that the ESP generally will have very little control over the message that you are sending. If you, the client, are not careful, then your mail stream will suffer from poor delivery due to poor reputation. As Laura points out concerning reputation:

ESPs, ISP Relations experts and delivery consultants can guide a sender through the process of repairing reputation. But the only thing that will actually improve reputation is changing sending practices.

Laura Atkins, ​Reputation​, Word to the Wise (2010), https://wordtothewise.com/2010/05/reputation-2/ (last visited May 30, 2024).

If you are not sending mail that people want, no ESP in the world can promise that your mail will get through.

Read moreBad Advice

Stay tuned. Next time, we’ll talk about Inbox Guarantees.

Mickey Chandler
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