+ http://rbl.dns-servicios.com/rbl.php
+ website can not be found
+ http://spamcannibal.org/
+ dead, as of at least 2018
+ http://st.technovision.dk/
+ https://docs.hetrixtools.com/st-technovision-dk-inactive-removed/
+ [December 8, 2021] This RBL has stopped responding to DNS queries.
+ http://spamstinks.com/
+ cert is for generic hostname
+ website shows some login form
+ http://virbl.bit.nl/
+ https://www.rollernet.us/2017/01/shutdown-of-virbl-dnsbl-bit-nl/
+ January 23, 2017: »The Virbl-project site has been replaced by this static message to inform those that find their ways here. The Virbl DNSBL-zone was emptied and will be removed all together at a moment further on in the future.«