344300ebd4
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.
45 lines
1.8 KiB
Python
45 lines
1.8 KiB
Python
"""Shared recipient-domain exclusions for outbound cold-email campaigns.
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We self-host our MTA (transactional relays like SES forbid cold email), so we
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must protect our sending-IP reputation manually. The single biggest lever is
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NOT mailing the Yahoo/Verizon-Media family: those providers aggressively defer
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cold senders with "unexpected volume / user complaints" 421 responses, which
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poisons the IP for every other provider too.
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Keep this list authoritative and import it everywhere we build audiences.
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"""
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from __future__ import annotations
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# Yahoo / Verizon Media operates ALL of these consumer domains. Legacy AT&T and
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# Frontier consumer mail was handed off to Yahoo's infrastructure as well.
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YAHOO_FAMILY_DOMAINS: frozenset[str] = frozenset({
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# Yahoo / AOL core
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"yahoo.com", "yahoo.com.mx", "yahoo.es", "yahoo.it", "yahoo.ca",
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"myyahoo.com", "ymail.com", "rocketmail.com",
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"aol.com", "aol.com.mx", "aim.com", "love.com", "games.com", "wow.com",
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"netscape.net", "netscape.com", "cs.com", "compuserve.com",
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# AT&T family (Yahoo-hosted)
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"att.net", "sbcglobal.net", "bellsouth.net", "pacbell.net",
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"ameritech.net", "swbell.net", "snet.net", "flash.net", "prodigy.net",
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"wans.net", "nvbell.net",
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# Verizon family (Yahoo-hosted)
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"verizon.net", "verizongni.com", "bellatlantic.net",
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# Frontier (Yahoo-hosted)
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"frontier.com", "frontiernet.net",
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})
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# The full set of consumer domains we refuse to cold-mail. Extend here as we
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# discover other reputation-sensitive providers.
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BLOCKED_EMAIL_DOMAINS: frozenset[str] = YAHOO_FAMILY_DOMAINS
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def domain_of(email: str) -> str:
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"""Return the lowercased domain part of an email, or '' if malformed."""
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if "@" not in email:
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return ""
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return email.rsplit("@", 1)[-1].strip().lower()
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def is_blocked(email: str) -> bool:
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return domain_of(email) in BLOCKED_EMAIL_DOMAINS
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