[Nmh-workers] Emails being tagged as spam -- NMH solution???

[Bob Carragher]

(I apologize if this has already been answered, or because this
is a more general, non-NMH-specific problem.  I'm guessing that
others on this list have encountered and solved this before.)

Emails that I send are starting to be tagged as spam or potential
spam more frequently these days.  (This has been happening for a
good while, but recently started to reach the "pain" threshold.)

As you can probably see from this message's header, my nominal
email provider is Google (@gmail.com) but my ISP is Comcast.  In
particular, they are not the same domain.  Nor are my Google
account's username and my machine's login ID the same (for
historical reasons).  So, even though I set up as much of my
composed message's header to reflect the @gmail.com account, it's
pretty clear that it's coming from someone else.  Hence, the
tagging of them by aggressive filters as spam.

Note:  since my machine login ID is a pretty common one, to avoid
my emails bounces going to someone else accidentally I set up
sendmail to specify my domain as @localhost.localdomain.  This no
doubt also contributes to the spam-tagging.

I'm guessing that one "simple" solution might be to purchase my
own domain, and then register it with GMail as an "equivalent
address" to "validate" my emails as non-spam.  I'd like to avoid
this if possible.

Has anyone else dealt with this situation successfully?  Is there
a solution that needs only NMH-level tweaking, or maybe an
adjustment to my sendmail's configuration?

Thanks!

                                Bob