How to query

Standard DNSBL convention. Reverse the octets of the IP address and append the zone. Examples use dnsbl.eu; the other three domains work identically.

These zones are not delegated yet. Treat this page as the reference for when they go live.

01IPv4 lookup

$ dig +short a 4.3.2.1.fresh.dnsbl.eu
127.0.0.2
$ dig +short a 4.3.2.1.spam.dnsbl.eu
$ dig +short a 4.3.2.1.repeat.dnsbl.eu
127.0.0.2

Querying 1.2.3.4 means asking for 4.3.2.1 under the zone. Each zone answers independently, so an address can be in one, two or all three.

02IPv6 lookup

Reverse all 32 nibbles, dot-separated, and append the zone, as in ip6.arpa.

03Microsoft tenant lookup

The ms zone is keyed on a Microsoft cross-tenant ID rather than an IP address. Use the tenant ID as the query label:

$ dig +short a 00000000-0000-0000-0000-000000000000.ms.dnsbl.eu

Tenant listings last 7 days. The example ID is a placeholder.

04Zone windows

Zone	Keyed on	Listed when
`fresh`	IP address	New in the last 24 hours
`spam`	IP address	New in the last 7 days
`repeat`	IP address	Seen more than once in the last 28 days
`ms`	Microsoft cross-tenant ID	Listed for 7 days

05Return codes

Answer	Meaning	Typical action
`127.0.0.2`	Listed in this zone	Reject or score, per zone
`NXDOMAIN`	Not listed in this zone	Accept

A TXT query on a listed entry returns a short human-readable reason. Draft return codes: final values still to be decided.

06Mail server examples

Postfix

smtpd_recipient_restrictions =
    permit_mynetworks,
    reject_unauth_destination,
    reject_rbl_client repeat.dnsbl.eu=127.0.0.2,
    reject_rbl_client spam.dnsbl.eu=127.0.0.2

rspamd

rbls {
  dnsbl_fresh  { rbl = "fresh.dnsbl.eu";  }
  dnsbl_spam   { rbl = "spam.dnsbl.eu";   }
  dnsbl_repeat { rbl = "repeat.dnsbl.eu"; }
}

Suggested use: score fresh lightly, treat repeat as the strongest signal.