README for Unbound 1.7.2
Copyright 2007 NLnet Labs
This software is under BSD license, see LICENSE for details.
The DNS64 module has BSD license in dns64/dns64.c.
The DNSTAP code has BSD license in dnstap/dnstap.c.
* Download the latest release version of this software from
or get a beta version from the svn repository at
* Uses the following libraries;
* libevent http://www.monkey.org/~provos/libevent/ (BSD license)
(optional) can use builtin alternative instead.
* libexpat (for the unbound-anchor helper program) (MIT license)
* Make and install: ./configure; make; make install
Can be set to either the system install or the build directory.
--with-libevent=no (default) gives a builtin alternative
implementation. libevent is useful when having many (thousands)
of outgoing ports. This improves randomization and spoof
resistance. For the default of 16 ports the builtin alternative
works well and is a little faster.
Can be set to the install directory of libexpat.
This disables pthreads. Without this option the pthreads library
is detected automatically. Use this option to disable threading
altogether, or, on Solaris, also use --with(out)-solaris-threads.
This enables assertions in the code that guard against a variety of
programming errors, among which buffer overflows. The program exits
with an error if an assertion fails (but the buffer did not overflow).
This enables a debug option to statically link against the
This enables a debug option to check lock and unlock calls. It needs
a recent pthreads library to work.
This enables a debug option to check malloc (calloc, realloc, free).
The server periodically checks if the amount of memory used fits with
the amount of memory it thinks it should be using, and reports
memory usage in detail.
Set default location of config file,
the default is /usr/local/etc/unbound/unbound.conf.
Set default location of pidfile,
the default is /usr/local/etc/unbound/unbound.pid.
Set default working directory,
the default is /usr/local/etc/unbound.
Set default chroot directory,
the default is /usr/local/etc/unbound.
Set the default root.key path. This file is read and written.
the default is /usr/local/etc/unbound/root.key
Set the default root update certificate path. A builtin certificate
is used if this file is empty or does not exist.
the default is /usr/local/etc/unbound/icannbundle.pem
Set default user name to change to,
the default is the "unbound" user.
Create libunbound wrapper usable from python.
Needs python-devel and swig development tools.
Compile the python module that processes responses in the server.
Disable support for RSASHA256 and RSASHA512 crypto.
Disable support for GOST crypto, RFC 5933.
* 'make test' runs a series of self checks.
o If there are no replies for a forward or stub zone, for a reverse zone,
you may need to add a local-zone: name transparent or nodefault to the
server: section of the config file to unblock the reverse zone.
Only happens for (sub)zones that are blocked by default; e.g. 10.in-addr.arpa
o If libevent is older (before 1.3c), unbound will exit instead of reload
on sighup. On a restart 'did not exit gracefully last time' warning is
printed. Perform ./configure --with-libevent=no or update libevent, rerun
configure and recompile unbound to make sighup work correctly.
It is strongly suggested to use a recent version of libevent.
o If you are not receiving the correct source IP address on replies (e.g.
you are running a multihomed, anycast server), the interface-automatic
option can be enabled to set socket options to achieve the correct
source IP address on UDP replies. Listing all IP addresses explicitly in
the config file is an alternative. The interface-automatic option uses
non portable socket options, Linux and FreeBSD should work fine.
o The warning 'openssl has no entropy, seeding with time', with chroot
enabled, may be solved with a symbolic link to /dev/random from <chrootdir>.
o On Solaris 5.10 some libtool packages from repositories do not work with
gcc, showing errors gcc: unrecognized option `-KPIC'
To solve this do ./configure libtool=./libtool [your options...].
On Solaris you may pass CFLAGS="-xO4 -xtarget=generic" if you use sun-cc.
o If unbound-control (or munin graphs) do not work, this can often be because
the unbound-control-setup script creates the keys with restricted
permissions, and the files need to be made readable or ownered by both the
unbound daemon and unbound-control.
o Crosscompile seems to hang. You tried to install unbound under wine.
wine regedit and remove all the unbound entries from the registry or
o Unbound was written in portable C by Wouter Wijngaards (NLnet Labs).
o Thanks to David Blacka and Matt Larson (Verisign) for the unbound-java
prototype. Design and code from that prototype has been used to create
this program. Such as the iterator state machine and the cache design.
o Other code origins are from the NSD (NLnet Labs) and LDNS (NLnet Labs)
projects. Such as buffer, region-allocator and red-black tree code.
o See Credits file for contributors.
NLnet Labs offers all of its software products as open source, most are
published under a BSD license. You can download them, not only from the
NLnet Labs website but also through the various OS distributions for
which NSD, ldns, and Unbound are packaged. We therefore have little idea
who uses our software in production environments and have no direct ties
with 'our customers'.
Therefore, we ask you to contact us at users@NLnetLabs.nl and tell us
whether you use one of our products in your production environment,
what that environment looks like, and maybe even share some praise.
We would like to refer to the fact that your organization is using our
products. We will only do that if you explicitly allow us. In all other
cases we will keep the information you share with us to ourselves.
In addition to the moral support you can also support us
financially. NLnet Labs is a recognized not-for-profit charity foundation
that is chartered to develop open-source software and open-standards
for the Internet. If you use our software to satisfaction please express
that by giving us a donation. For small donations PayPal can be used. For
larger and regular donations please contact us at users@NLnetLabs.nl. Also