1.6 KiB
1.6 KiB
Enable DNSBL service in Postfix to reduce spam
!!! attention
If you're running a high-traffic mail server, you'd better setup a local
DNS server to cache DNS queries, because free RBL services like
`zen.spamhaus.org` may improperly reply if your server exceed the DNS
query limit. Also, mail service higly relies on DNS queries, so a local
DNS server speeds up the mail flow.
You can enable additional DNSBL services in Postfix to reduce spam. We use
zen.spamhaus.org
for example below.
- Open Postfix config file
/etc/postfix/main.cf
or/usr/local/etc/postfix/main.cf
(on FreeBSD), appendreject_rbl_client zen.spamhaus.org
to parametersmtpd_recipient_restrictions
. Final setting looks like below:
smtpd_recipient_restrictions =
...
reject_unauth_destination
reject_rbl_client zen.spamhaus.org
It must be placed after reject_unauth_destination
. You can add more DNSBL
services after reject_unauth_destination
, and they will be queried in the
specified order.
- Restart or reload Postfix service is required.
!!! note "Another popular DNSBL server"
Another popular DNSBL server address is `b.barracudacentral.org`. For more
details, please read its web site:
[Barracuda Reputation Block List (BRBL)](http://www.barracudacentral.org/rbl)