November 17, 2009

E-mail failure rates

People seem to think that ALL email gets through. It doesn't!

In fact, the U.S. Post Office, for all its problems, actually has a dramatically better delivery rate.

Research by Microsoft and others estimates that only about 99% of legitimate, non-spam email gets through. At first blush, that sounds pretty good.

In fact, it means that in a normal week, someone sends me a message about stocks and bonds that does not reach me. Unless that unknown contributor contacts me again, I won't even know the message was lost. Last week, I learned that two genealogy-related messages failed to reach me.

Obviously, many losses are due to aggressive spam filtering somewhere along the email transmittal path. Normally, the most aggressive spam filtering takes place at the last step before final delivery.

However, I used to have one contributor who could reliably get mail to me only by sending to my private Comcast account. After detective work, my ISP tracked the problem down to an overly aggressive spam filter on a single bank of servers on the East Coast. That filter was blocking all email from my correspondent's ISP which operated in eastern France and western Germany. The person who owned those particular East Coast servers refused to budge on his overly-zealous spam filtering protocol. Fortunately, email sent to my Comcast account avoided that self-appointed hall monitor.

The good thing about spam filters is that recipients can usually request their ISP (Internet service provider) to "white list" email from specific sources. I periodically make sure my correspondents are "white listed" in order to assure their email gets through unimpeded. Having problems with specific email not getting through? Tell your ISP.

Unfortunately, there are non-trivial numbers of losses caused by accidental infrastructure failures between sender and recipient. This would be the equivalent of real-life postal trucks driving into rivers every few days and losing all their letters. While everyone expects redundancy and data backups would prevent the problem, losses still occur.

Like I said, about 1% of email is lost.!

I bring this up simply to alert you that if I (or any other correspondent) do not respond to you in a reasonable amount of time, it is possible your message got lost. It happens. Why not ask if I got your message?

1 comment:

Email Spam Protection said...

Informative post. Good useful article. Thanks.