Excessive Bounces

[Jay West]

I did dig into this for Rob, as well as a smattering of others that got
disabled yesterday early am.

Almost 100% of the email addresses that get disabled due to excessive
retries are Hotmail, aol, and yahoo.  Those email providers are well known
as "less than reliable" to many servers, often because they are major
sources of spam.

Of those bounces, almost 100% of them were due to DMARC/DKIM mechanisms. I
view DMARC/DKIM as less than useless. First, they are far from universally
implemented - so most valid email is not DMARC/DKIM "protected". Second a
large percentage of the spam in the world *IS* DMARC/DKIM "protected".

What is odd to me, many of the email addresses (list members) that get
dropped due to excessive retries are listmembers who *DO* get list traffic
for a while before getting occasionally disabled. I would bet that what is
happening most of the time is that their ISP maintains a flock of MX hosts
and at one time decided to implement DKIM/DMARC but then realized it's a bad
idea and removed it from service but forgot to do that on one or two of the
flock. Thus... by happenstance once in a while your email hits that
particular mx host and gets toasted. The reverse is certainly possible -
that they are "beta testing" it on a few of their MX hosts but not wanting
to do it everywhere.

Please, let's not go into a long thread of the merits of SPF/DKIM/DMARC...
I'm just letting folks know what is probably responsible for most of the
"subscription disabled..." stuff. 

J