Warmup audit (2026-06-08) found the main sending pool was eating a 37% bounce
rate, and 556 of those were Google 550-5.7.1 'likely unsolicited mail' spam
blocks -- of which gmail.com alone was 427 (77%). Google's cold-IP filter is the
strictest of the big providers and consumer gmail has the highest complaint
sensitivity, so mailing it from a warming IP is pure reputation damage.
Added GOOGLE_CONSUMER_DOMAINS (gmail.com, googlemail.com) to BLOCKED_EMAIL_DOMAINS,
which the daily trucking builder already enforces in its recipient SQL
(lower(domain) <> ALL(blocked)). Takes effect on the next nightly build.
Custom domains silently on Google Workspace are a smaller (~5%) MX-only signal,
already handled in the healthcare builder via the mx_provider flag; can be ported
to the main pool later if the residual warrants it.
Yahoo operates a large family of consumer domains (AOL, AT&T, Verizon,
Frontier, sbcglobal, bellsouth, etc.) that aggressively defer cold senders
with 421 'unexpected volume / user complaints', which poisons our self-hosted
sending IP for every other provider. Previously we only excluded
aol.com/yahoo.com/ymail.com/rocketmail.com.
Centralize the authoritative block list in scripts/_email_exclusions.py and
import it from both audience builders so they stay in sync.
