Install BIND nameserver in a chroot on Debian 6

Wednesday, October 17, 2012 posted by Till

This tutorial is about chrooting a BIND (named) installation on Debian 6. Chrooting is used for security reasons, in case that BIND gets hacked on the server, the hacker is jailed into the chroot and can not get access to other services.

 

Installation

 

apt-get install bind9

to install BIND9.

For security reasons we want to run BIND chrooted so we have to do the following steps:

/etc/init.d/bind9 stop

Edit the file /etc/default/bind9 so that the daemon will run as the unprivileged user bind, chrooted to /var/lib/named. Modify the line: OPTIONS=”-u bind” so that it reads OPTIONS=”-u bind -t /var/lib/named”:

vi /etc/default/bind9

# run resolvconf?
RESOLVCONF=yes

# startup options for the server
OPTIONS=”-u bind -t /var/lib/named”
Create the necessary directories under /var/lib:

mkdir -p /var/lib/named/etc
mkdir /var/lib/named/dev
mkdir -p /var/lib/named/var/cache/bind
mkdir -p /var/lib/named/var/run/bind/run

Then move the config directory from /etc to /var/lib/named/etc:

mv /etc/bind /var/lib/named/etc

Create a symlink to the new config directory from the old location (to avoid problems when BIND gets updated in the future):

ln -s /var/lib/named/etc/bind /etc/bind

Make null and random devices, and fix permissions of the directories:

mknod /var/lib/named/dev/null c 1 3
mknod /var/lib/named/dev/random c 1 8
chmod 666 /var/lib/named/dev/null /var/lib/named/dev/random
chown -R bind:bind /var/lib/named/var/*
chown -R bind:bind /var/lib/named/etc/bind

We need to create the file /etc/rsyslog.d/bind-chroot.conf…

vi /etc/rsyslog.d/bind-chroot.conf

… with the following line so that we can still get important messages logged to the system logs:

$AddUnixListenSocket /var/lib/named/dev/log

Restart the logging daemon:

/etc/init.d/rsyslog restart

Start up BIND, and check /var/log/syslog for errors:

/etc/init.d/bind9 start

Thanks to Falko Timme from Howtoforge.com for this tutorial.

 

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