Listing on the ZapBL indicates that a ZapBL admin email address or spam trap received spam that advertized the listed domain. ZapBL is a blacklist comprised of IP addresses that ZapBL admins and others using their blacklist do not want to receive mail from. ZapBL avoids listing IP addresses for Backscatter with an exception for when email systems reply to spam or viruses with rejection reports stating they've detected spam or viruses".
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