dnsrbl

make sure the DNSRBL lists you are targeting are still alive. the test can be done according to the very specific RBL mechanism and using generic listing.

for zone in \
    bl.spamcop.net \
    public.sarbl.org \
    cbl.abuseat.org \
    psbl.surriel.com \
    db.wpbl.info \
    ix.dnsbl.manitu.net \
    b.barracudacentral.org \
    dnsbl.inps.de \
    bl.blocklist.de \
    spam.spamrats.com \
    truncate.gbudb.net \
    dnsbl.dronebl.org \
    zen.spamhaus.org \
    ; do
    echo $zone
    host 2.0.0.127.$zone && echo OK || echo NOK
    echo
done; unset zone

some notes about too restrictive lists

# this sometimes blocks gmail...
#   dnsbl.dronebl.org

# this blocks hh.ru
#        truncate.gbudb.net

# this blocks nine.pairlist.net / hackrf-dev-bounces@greatscottgadgets.com
#       spam.spamrats.com

# those block orange.fr...
#       dnsbl.sorbs.net
#       dnsbl-1.uceprotect.net
# http://www.uceprotect.net/en/index.php?m=6&s=11

# apews is blocking online.net ip range
#       l2.apews.org

# this is too restrictive
#       reject_rhsbl_sender dsn.rfc-clueless.org

those are closed

# The RFC-Ignorant.org DNS lists are closed effective 2012-10-30.
#       reject_rhsbl_sender bogusmx.rfc-ignorant.org,
#       reject_rhsbl_sender dsn.rfc-ignorant.org,

resources

https://web.archive.org/web/20140213185822/http://spamlinks.net/filter-dnsbl-dead.htm

https://www.spamhaus.org/faq/section/DNSBL%20Usage

https://www.barracudacentral.org/rbl/how-to-use

https://www.dnsbl.com/2008/10/shutting-down-blacklists.html

https://www.sarbl.org/Main

Welcome to DNSBL.info https://www.dnsbl.info/

dnsbl resource https://www.dnsbl.com/

Which DNSBLs work well? https://www.dnsbl.com/2007/03/how-well-do-various-blacklists-work.html

What are spamtraps? https://www.spamresource.com/2007/02/what-are-spamtraps.html

Mail Spam Blacklists https://linuxreviews.org/Mail_Spam_Blacklists

w3bservice/Current Effective RBL Setup for Postfix 2017 https://gist.github.com/w3bservice/16f500e6c745aa6f3e6542ddc239c3c0

Postfix configure anti spam with blacklist https://www.cyberciti.biz/tips/postfix-spam-filtering-with-blacklists-howto.html

Blacklist & Whitelist with Postfix https://linuxlasse.net/linux/howtos/Blacklist_and_Whitelist_with_Postfix

Mimecast SMTP Error Codes https://community.mimecast.com/docs/DOC-1369

Prevent spam in Postfix https://support.rackspace.com/how-to/prevent-spam-in-postfix/

How-To: Fight SPAM with Postfix RBL https://www.debuntu.org/how-to-fight-spam-with-postfix-rbl/

https://www.linuxmagic.com/power_of_ip_reputation https://www.linuxmagic.com/products/bms/ https://www.linuxmagic.com/products/bms/blacklist_info https://www.linuxmagic.com/products/bms/mail_servers http://linuxmagic.ca/products/bms/install http://www.linuxmagic.ca/products/bms/whitelists

https://www.spamrats.com/about.php

https://www.mipspace.com/