- supports SMTP authentication - that is, users can bypass the blacklist listing by authenticating via SMTP AUTH
- supports sender address verification or sender callbacks (see milter-sender) - most SMTP callbacks are made using the null-envelope sender address. When we see this, we defer our blacklist checks until the SMTP DATA stage (or xxfi_data() callback in Sendmail 8.14.0+'s milter API)
- customizable blacklists (defaults are SpamCop, Spamhaus, The Passive Spam Block List (PSBL), and Barracuda Reputation Block List (BRBL)) and whitelists (default is to use DNSWL.org) - we chose these blacklists and whitelists due to various documents online comparing some of the popular blacklists. See links provided in the "Links" section
- . . . and more. . .
So why choose dnsbl-milter over Sendmail's builtin dnsbl/enhdnsbl feature?
- allows use of DNS whitelists to override DNS blacklist listings
- allows more control as to what IPs/ports (daemon_options) we want DNSBL filtering
- relay lines does not override listing (See 510 Software Group's explanation)
- . . . and more to come
SourceForge.net Git Repository
That's it. Watch the logs and watch your spam drop.
- check source, make sure DNSBLs and DNSWLs are the ones you want. By default, we're using SpamCop, Spamhaus and DNSWL.org
- compile source
- install compiled program
# make install
- add something like the line below to sendmail.mc file:
INPUT_MAIL_FILTER(`dnsbl-milter', `S=unix:/var/run/milter/dnsbl-milter.sock, T=C:5m;S:20s;R:5m;E:10m, F=T')dnl
- add "dnsbl-milter" to the "InputMailFilters" parameter in DAEMON_OPTIONS
- generate new sendmail.cf file from sendmail.mc
- run dnsbl-milter manually or use the init.d script provided in the source repository.
# /usr/local/sbin/dnsbl-milter --user milter --group milter --bind unix:/var/run/milter/dnsbl-milter.sock --daemon
Report bugs, post patches, request new features, get support. . .
Other similar milters
dnsbl Sendmail milter