邮件服务器黑名单查询网站
可在以下网站查询IP或域名是否被加入黑名单:
https://www.dnsbl.info/
https://mxtoolbox.com/blacklists.aspx
http://whatismyipaddress.com/blacklist-check
http://www.spamhaus.org/
http://www.kloth.net/services/dnsbl.php
http://www.anti-abuse.org/multi-rbl-check-results/