After much futzing and experimentation, I think I was able to work around the problem causing:
"The email sample ... appears to traverse more than one domain" (on validating [SpamCop] account configuration email)
Host pdx1-sub0-mail-mx210.dreamhost.com (checking ip) IP not found ; pdx1-sub0-mail-mx210.dreamhost.com discarded as fake.
Sorry, SpamCop has encountered errors:
The email sample you submitted for gconnor@nekodojo.org
appears to traverse more than one domain.
Please ensure that you configure each mailhost individually and in order.
In the headers of the "account configuration email" when submitting them back to Spamcop, I changed this line:
by pdx1-sub0-mail-mx206.dreamhost.com (Postfix) with ESMTPS id 4T07790vPyz7dnP
and just shortened the fake/internal hostname that Spamcop had the problem with to just "dreamhost.com"
by dreamhost.com (Postfix) with ESMTPS id 4T07790vPyz7dnP
This also seemed to work when submitting the spam email for analysis.
My guess here is that "mailchannels.net" receives the mail and then forwards it to "dreamhost.com" but the dreamhost server is configured with an internal name that doesn't exist in DNS. Dreamhost could probably fix this by configuring Postfix to use a proper DNS name for its "by" lines or just writing "by dreamhost.com"
@Ken Simpson you might not be able to fix this from Mailchannels side but you might have a contact at Dreamhost to help them configure Postfix with real names?
