Friday, July 8, 2011

How to enable DNSBL configuration in Sendmail | enhdnsbl | Enable Domain Black List

Domain Name System Blacklists, also known as DNSBL's or DNS Blacklists, are spam blocking lists that allow a website administrator to block messages from specific systems that have a history of sending spam.
To enable external DSN based blacklist feature on your sendmail server, you can add the below mentioned configuration in the file located in /etc/mail . Below I have mentioned eight dnsbl configurations, You can choose the black list based on your environment, server load etc and add it .
#vim /etc/mail/
FEATURE(`enhdnsbl', `', `"Spam blocked see:"$&{client_addr}', `t')
FEATURE(dnsbl,`',`Message from $&{client_addr} rejected - see$&{client_addr}')
FEATURE(rhsbl,`',`"550 Mail from domain " $`'&{RHS} " refused. MX of domain do not accept bounces. This violates RFC 821/2505/2821 - see"')
FEATURE(`dnsbl', `', `"Rejected due to Spamhaus listing see" $&{clientaddr} " for more information"')


Restart the sendmail service
#service sendmail restart

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