Spamhaus has the limitation for DNS queries from one host. If you are using MailScanner DNSBL Check please edit the configuration under
# By default, SpamAssassin will run RBL checks. If your ISP already
# does this, stop RBL checks in SpamAssassin by un-commenting the
# following line
This will make sure the DNSBL queries is only used by MailScanner not by Spamassassin to scan the same email.
We also received spam from people that used Googlegroup and Yahoogroup. For temporary solution we have disabled Auto Whitelist because it produced failed positive for this type of spam.
# The --auto-whitelist and -a options for "spamd" and "spamassassin" to
# turn on the auto-whitelist have been removed and replaced by the
# "use_auto_whitelist" configuration option which is also now turned on by
Please also check the /etc/mail/spamassassin/mailscanner.cf and remark those setting so that the setting inside /etc/mail/spamassassin/local.cf will be used.
Please refer to my other blog posts
Email Spam Filtering Next Level
MailScanner To Used MCP