---
name: "rbldns"
section: "8"
platform: "linux"
package: "rbldns"
version: "1:1.05-22"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/rbldns"
---

# rbldns(8)

an IP-address-listing DNS server

## NAME

rbldns - an IP-address-listing DNS server

## DESCRIPTION

**rbldns** is an IP-address-listing DNS server. It accepts iterative DNS queries from hosts around the Internet asking about various IP addresses. It provides responses showing whether the addresses are on a locally configured list, such as RBL or DUL.

## Configuration

Normally  **rbldns** is set up by the [**rbldns-conf**(8)](/rbldns-conf/8.md) program.

**rbldns** runs chrooted in the directory specified by the  *$ROOT* environment variable, under the uid and gid specified by the  *$UID* and  *$GID* environment variables.

**rbldns** listens for incoming UDP packets addressed to port 53 of  *$IP*. It does not listen for TCP queries.

**rbldns** handles domains of the form *d.c.b.a.base* where  *a.b.c.d* is the IP address in question and  *base* is given by the  *$BASE* environment variable.

**rbldns** rejects inverse queries, non-Internet-class queries, truncated packets, packets that contain anything other than a single query, query types other than A, TXT, or \*, and queries for domains outside  *$BASE*. It looks up other queries inside  *data.cdb*, a binary file created by [**rbldns-data**(8)](/rbldns-data/8.md).

## SEE ALSO

[rbldns-conf(8)](/rbldns-conf/8.md), [rbldns-data(8)](/rbldns-data/8.md)

http://cr.yp.to/djbdns.html