---
title: "NXDOMAIN Redirection Using DLZ in BIND 9.10 and later"
slug: "aa-01150"
description: "NXDOMAIN redirection is a BIND feature that allows a recursive server to replace an NXDOMAIN response to a query with a configured answer of its own."
updated: 2018-09-17T22:39:07Z
published: 2018-09-17T22:39:07Z
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://kb.isc.org/llms.txt
> Use this file to discover all available pages before exploring further.

# NXDOMAIN Redirection Using DLZ in BIND 9.10 and later

@(Info)(This feature is also available in BIND 9.9-S)(All information below also applies to BIND 9.9 Subscription Version.)

NXDOMAIN redirection is a BIND feature providing the ability for a recursive server to replace an NXDOMAIN response to a query with a configured answer of its own.  This substitute response is returned to the original client in place of the NXDOMAIN response received by the server.  Recursive server administrators may use this redirection for their own purposes or to obtain advertising revenue from third parties who specialize in this business.  Use of this feature is optional and the default is off.  Unless the default behavior is overridden by the administrator a recursive BIND resolver will pass NXDOMAIN responses to the querying client without altering them.


The NXDOMAIN redirection feature debuted originally in BIND 9.9.0, and allowed simple redirection of NXDOMAIN responses based on the use of a new zone type (`type redirect`).  This [original method of NXDOMAIN redirection](https://kb.isc.org/docs/aa-00376) remains supported, but in addition BIND 9.10 expands upon this feature by extending the Dynamically Loadable Zones (DLZ) feature set to allow more flexible control over NXDOMAIN responses.



As a side benefit of the improved DLZ support, BIND 9.10 and later allows operators to configure multiple DLZ data sources and specify their ordering.



In order to use a dynamically loadable zone, it must first be declared in a `dlz` definition block which specifies a data source and (optionally) declares the database to be searchable or not searchable.  The `dlz` declaration looks like this:

```
dlz "example" {
     database "dlopen driver.so database.name";
     search yes;    // the "search" line is optional; if unspecified it defaults to "yes"
};
```

The `search` keyword is new to the expanded DLZ support in BIND 9.10 and later.


* If `search` is set to `yes` (or is unspecified) then the data source declared in that DLZ declaration is searched as part of the "best-match" fitting when a query comes in that is not covered by a regular zone.
* If `search` is set to `no`, that data source is not used for "best-match" fitting but only where it is explicitly declared for use in a zone definition.

To use NXDOMAIN redirection with DLZ, configure a `dlz` declaration pointing to a database that will return the desired redirect answer and use the `search no;` option in your declaration:

```
dlz "nxdomain.redirect" {
     database "dlopen driver.so redirect.database";
     search no;
};
```

And then instruct `named` to use that as the data source for a zone definition of type `redirect`.

```
zone . {
     type redirect;
     dlz nxdomain.redirect;
};
```