SpamCop

SpamCop provides a Real-time Blackhole List (RBL) that mail servers can use to determine if incoming mail should be marked as spam. Today, mail administrators, organizations, and ISPs worldwide suddenly found that their outgoing mail was being rejected as it reported as being listed in the blacklist at bl.spamcop.net. It turns out that this was a false positive caused by the spamcop.net domain expiring yesterday and causing mail servers who use their RBL to reject incoming mail automatically.