diff --git a/scripts/_email_exclusions.py b/scripts/_email_exclusions.py
index 7d0a9db..d3b5698 100644
--- a/scripts/_email_exclusions.py
+++ b/scripts/_email_exclusions.py
@@ -70,11 +70,43 @@ DO_NOT_CONTACT_EMAILS: frozenset[str] = frozenset({
     "dave@dataspindle.com",
 })
 
+# Defunct / legacy / satellite ISP mailbox domains. Cold-mailing these is pure
+# reputation drag: the mailboxes are overwhelmingly dead (the brand was shut down
+# or absorbed years ago and the addresses now hard-bounce) or the operator
+# (satellite / small rural ISP) aggressively defers cold B2B mail with poor
+# eventual delivery. Identified from our own Listmonk bounce table (top bounced
+# recipient domains) cross-checked against ISP status. NOTE: still-active large
+# consumer ISPs (comcast.net, charter.net, cox.net, centurylink.net) are
+# deliberately NOT here -- their bounces were the cold-IP/no-DKIM reputation
+# problem (now fixed), not dead mailboxes, and they carry real prospects.
+DEAD_ISP_DOMAINS: frozenset[str] = frozenset({
+    # Defunct dial-up / early-ISP brands (mail shut down or vestigial)
+    "earthlink.net", "peoplepc.com", "mindspring.com", "netzero.net",
+    "netzero.com", "juno.com", "excite.com", "lycos.com", "wmconnect.com",
+    "adelphia.net", "voyager.net", "core.com", "localnet.com", "pldi.net",
+    "ptsi.net", "cablespeed.com",
+    # CenturyLink / Qwest / Embarq legacy brands (migrated/abandoned)
+    "qwest.net", "qwestoffice.net", "embarqmail.com", "centurytel.net",
+    "citlink.net", "citynet.net",
+    # Satellite (poor cold-mail deliverability, high defer/bounce)
+    "hughes.net", "wildblue.net", "dishmail.net", "wildblueinternet.net",
+    # Altice / Optimum / Suddenlink / Cablevision family (rural, aggressive defer)
+    "optonline.net", "suddenlink.net", "cebridge.net", "bresnan.net",
+    # WOW! / Knology, Mediacom, Insight, Atlantic Broadband/Breezeline, Cable One
+    "wowway.com", "knology.net", "mchsi.com", "insightbb.com", "atlanticbb.net",
+    "breezeline.net", "cableone.net", "cableone.com",
+    # Small / rural regional ISPs (aggressive defer, low cold deliverability)
+    "windstream.net", "tds.net", "iowatelecom.net", "netins.net", "mhtc.net",
+    "arvig.net", "consolidated.net", "fuse.net", "ncn.net", "new.rr.com",
+    # Alaska regional (satellite/long-haul, poor cold deliverability)
+    "gci.net", "alaska.net", "acsalaska.net", "gulftel.com",
+})
+
 # The full set of consumer domains we refuse to cold-mail. Extend here as we
 # discover other reputation-sensitive providers.
 BLOCKED_EMAIL_DOMAINS: frozenset[str] = (
     YAHOO_FAMILY_DOMAINS | GOOGLE_CONSUMER_DOMAINS | MICROSOFT_CONSUMER_DOMAINS
-    | DO_NOT_CONTACT_DOMAINS
+    | DEAD_ISP_DOMAINS | DO_NOT_CONTACT_DOMAINS
 )