Difference between revisions of "BIND"

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[[Category:Domain Name System]]
 
[[Category:Domain Name System]]
 
[[de:BIND]]
 
[[de:BIND]]
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[[es:BIND]]
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[[fr:BIND]]
 
[[ja:BIND]]
 
[[ja:BIND]]
[[zh-CN:BIND]]
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[[zh-hans:BIND]]
Berkeley Internet Name Daemon (BIND) is the reference implementation of the Domain Name System (DNS) protocols.
+
{{Related articles start}}
 +
{{Related|DNSCrypt}}
 +
{{Related|dnsmasq}}
 +
{{Related|Pdnsd}}
 +
{{Related|Unbound}}
 +
{{Related|PowerDNS}}
 +
{{Related articles end}}
 +
{{Style|Numerous style and content issues.}}
 +
[https://www.isc.org/downloads/bind/ BIND] (or named) is the most widely used Domain Name System (DNS) server.
 +
 
 +
{{Note|The organization developing BIND is serving security notices to paying customers up to four days before Linux distributions or the general public.[https://kb.isc.org/article/AA-00861/0/ISC-Software-Defect-and-Security-Vulnerability-Disclosure-Policy.html]}}
  
 
== Installation ==
 
== Installation ==
These few steps show you how to install BIND and set it up as a local caching-only server.
 
  
[[pacman|Install]] the {{Pkg|bind}} package which can be found in the [[Official Repositories|official repositories]].
+
[[Install]] the {{Pkg|bind}} package.
  
Optionally edit {{ic|/etc/named.conf}} and add this under the options section, to only allow connections from the localhost:
+
[[Start/enable]] the {{ic|named.service}} systemd unit.
 +
 
 +
To use the DNS server locally, use the {{ic|127.0.0.1}} nameserver, see [[Domain name resolution]].
 +
This will however require you to [[#Allow recursion]].
 +
 
 +
== Configuration ==
 +
 
 +
BIND is configured in {{ic|/etc/named.conf}}. The available options are documented in {{man|5|named.conf}}.
 +
 
 +
[[Reload]] the {{ic|named.service}} unit to apply configuration changes.
 +
 
 +
===Restrict access to localhost===
 +
 
 +
BIND by defaults listens on all interfaces and IP addresses.
 +
 
 +
To only allow connections from localhost add the following line to the options section in {{ic|/etc/named.conf}}:
 
  listen-on { 127.0.0.1; };
 
  listen-on { 127.0.0.1; };
  
Edit {{ic|/etc/resolv.conf}} to use the local DNS server:
+
=== Set up DNS forwarding ===
nameserver 127.0.0.1
 
  
[[Daemon#Managing daemons|Start]] the '''named''' daemon.
+
To make BIND forward DNS queries to another DNS server add the forwarders clause to the options section.
 +
 
 +
Example to make BIND forward to the Google DNS servers:
 +
 
 +
forwarders { 8.8.8.8; 8.8.4.4; };
  
 
== A configuration template for running a domain ==
 
== A configuration template for running a domain ==
 +
 
This is a simple tutorial in howto setup a simple home network DNS-server with bind. In our example we use "domain.tld" as our domain.
 
This is a simple tutorial in howto setup a simple home network DNS-server with bind. In our example we use "domain.tld" as our domain.
  
 
For a more elaborate example see [http://www.howtoforge.com/two_in_one_dns_bind9_views Two-in-one DNS server with BIND9].
 
For a more elaborate example see [http://www.howtoforge.com/two_in_one_dns_bind9_views Two-in-one DNS server with BIND9].
  
=== 1. Creating a zonefile ===
+
Another guide at [http://www.brennan.id.au/08-Domain_Name_System_BIND.html#yourdomain Linux Home Server HOWTO - Domain name system (BIND): Adding your domain] will show you how to set up internal network name resolution in no time; short, on-point and very informative.
# nano /var/named/domain.tld.zone
+
 
 +
=== Creating a zonefile ===
 +
 
 +
Create {{ic|/var/named/domain.tld.zone}}.
  
 
  $TTL 7200
 
  $TTL 7200
Line 49: Line 82:
 
$TTL defines the default time-to-live in seconds for all record types. In this example it is 2 hours.
 
$TTL defines the default time-to-live in seconds for all record types. In this example it is 2 hours.
  
Serial must be incremented manually before restarting named every time you change a resource record for the zone. If you forget to do it slaves will not re-transfer the zone: they only do it if the serial is greater than that of the last time they transferred the zone.
+
'''Serial must be incremented manually before restarting named every time you change a resource record for the zone.''' If you forget to do it slaves will not re-transfer the zone: they only do it if the serial is greater than that of the last time they transferred the zone.
 +
 
 +
=== Configuring master server ===
  
=== 2. Configuring master server ===
 
 
Add your zone to {{ic|/etc/named.conf}}:
 
Add your zone to {{ic|/etc/named.conf}}:
 
  zone "domain.tld" IN {
 
  zone "domain.tld" IN {
Line 60: Line 94:
 
  };
 
  };
  
Restart the daemon and you are done.
+
[[Reload]] the {{ic|named.service}} unit to apply the configuration change.
 +
 
 +
== Allow recursion ==
 +
 
 +
If you are running your own DNS server, you might as well use it for all DNS lookups.  This will require the ability to do ''recursive'' lookups.  In order to prevent [https://www.us-cert.gov/ncas/alerts/TA13-088A DNS Amplification Attacks], recursion is turned off by default for most resolvers.  The default Arch {{ic|/etc/named.conf}} file allows for recursion only on the loopback interface:
 +
 
 +
allow-recursion { 127.0.0.1; };
  
== BIND as simple DNS forwarder ==
+
{{Accuracy|LAN networking isn't recursive.}}
If you have problems with, for example, VPN connections, they can sometimes be solved by setting-up a forwarding DNS server. This is very simple with BIND. Add these lines to {{ic|/etc/named.conf}}, and change IP address according to your setup.
+
 
  listen-on { 192.168.66.1; };
+
If you want to provide name service for your local network; e.g. 192.168.0.0/24, you must add the appropriate range of IP addresses to {{ic|/etc/named.conf}}:
forwarders { 8.8.8.8; 8.8.4.4; };
+
 
Don't forget to restart the service!
+
  allow-recursion { 192.168.0.0/24; 127.0.0.1; };
 +
 
 +
== Configuring BIND to serve DNSSEC signed zones ==
 +
 
 +
{{Expansion|This is just a list of links.}}
 +
 
 +
* http://www.dnssec.net/practical-documents
 +
** http://www.cymru.com/Documents/secure-bind-template.html '''(configuration template!)'''
 +
** http://www.bind9.net/manuals
 +
** http://www.bind9.net/BIND-FAQ
 +
* http://blog.techscrawl.com/2009/01/13/enabling-dnssec-on-bind/
 +
* Or use an external mechanisms such as OpenDNSSEC (fully-automatic key rollover)
 +
 
 +
== Automatically listen on new interfaces ==
 +
 
 +
By default bind scan for new interfaces and stop listening on interfaces which no longer exist every hours. You can tune this value by adding :
 +
interface-interval <rescan-timeout-in-minutes>;
 +
parameter into {{ic|named.conf}} options section. Max value is 28 days. (40320 min) <br>
 +
You can disable this feature by setting its value to 0.
 +
 
 +
Then restart the service.
  
 
== Running BIND in a chrooted environment ==
 
== Running BIND in a chrooted environment ==
Running in a [[chroot]] environment is not required but improves security. See [[BIND (chroot)]] for how to do this.
 
  
== Configuring BIND to serve DNSSEC signed zones ==
+
Running in a [[chroot]] environment is not required but improves security.
See [[DNSSEC#BIND (serving signed DNS zones)]]
+
 
 +
=== Creating the Jail House ===
 +
In order to do this, we first need to create a place to keep the jail, we shall use {{ic|/srv/named}}, and then put the required files into the jail.
 +
 
 +
  mkdir -p /srv/named/{dev,etc,usr/lib/engines,var/{run,log,named}}
 +
  # Copy over required system files
 +
  cp -av /etc/{localtime,named.conf} /srv/named/etc/
 +
  cp -av /usr/lib/engines-1.1/* /srv/named/usr/lib/engines/
 +
  cp -av /var/named/* /srv/named/var/named/.
 +
  # Set up required dev nodes
 +
  mknod /srv/named/dev/null c 1 3
 +
  mknod /srv/named/dev/random c 1 8
 +
  # Set Ownership of the files
 +
  chown -R named:named /srv/named
 +
 
 +
This should create the required file system for the jail.
 +
 
 +
=== Service File ===
 +
 
 +
Next we need to create the new service file which will allow force bind into the chroot
  
== Automatically listen on new interfaces without chroot and root privileges ==
+
   cp -av /usr/lib/systemd/system/named.service /etc/systemd/system/named-chroot.service
{{Out of date|initscripts have been replaced by systemd}}
 
Add
 
   interface-interval <rescan-timeout-in-minutes>;
 
parameter into {{ic|named.conf}} options. Then you should modify rc-script:
 
<pre>
 
    stat_busy "Starting DNS"
 
-   [ -z "$PID" ] && /usr/sbin/named ${NAMED_ARGS}
 
+    setcap cap_net_bind_service=eip /usr/sbin/named
 
+    NAMED_ARGS=`echo ${NAMED_ARGS} | sed 's#-u [[:alnum:]]*##'`
 
+    [ -z "$PID" ] && sudo -u named /usr/sbin/named ${NAMED_ARGS}
 
</pre>
 
  
So your {{ic|/etc/rc.d/named}} should look like this:
+
we need to edit how the service calls bind.
<pre>
 
    stat_busy "Starting DNS"
 
    setcap cap_net_bind_service=eip /usr/sbin/named
 
    NAMED_ARGS=`echo ${NAMED_ARGS} | sed 's#-u [[:alnum:]]*##'`
 
    [ -z "$PID" ] && sudo -u named /usr/sbin/named ${NAMED_ARGS}
 
</pre>
 
  
Change user name in last line (with "... sudo -u named ...") if your named user is not 'named'.
+
{{hc|/etc/systemd/system/named-chroot.service|<nowiki>
 +
  ExecStart=/usr/bin/named -4 -f -u named -t "/srv/named"
 +
</nowiki>}}
  
==See also==
+
How, restart the systemd service.
*[[BIND (chroot)]]
 
  
== BIND Resources ==
+
== See also ==
 +
* [https://www.isc.org/downloads/bind/doc/ BIND 9 Administrator Reference Manual]
 
* [http://www.reedmedia.net/books/bind-dns/ BIND 9 DNS Administration Reference Book]
 
* [http://www.reedmedia.net/books/bind-dns/ BIND 9 DNS Administration Reference Book]
 +
* [http://shop.oreilly.com/product/9780596100575.do DNS and BIND by Cricket Liu and Paul Albitz]
 
* [http://www.netwidget.net/books/apress/dns/intro.html Pro DNS and BIND]
 
* [http://www.netwidget.net/books/apress/dns/intro.html Pro DNS and BIND]
 
* [http://www.isc.org/ Internet Systems Consortium, Inc. (ISC)]
 
* [http://www.isc.org/ Internet Systems Consortium, Inc. (ISC)]
 
* [http://www.menandmice.com/knowledgehub/dnsglossary DNS Glossary]
 
* [http://www.menandmice.com/knowledgehub/dnsglossary DNS Glossary]
 +
* [https://lists.archlinux.org/pipermail/arch-dev-public/2013-March/024588.html Archived mailing list discussion on BIND's future]

Latest revision as of 06:58, 24 May 2018

Tango-edit-clear.pngThis article or section needs language, wiki syntax or style improvements.Tango-edit-clear.png

Reason: Numerous style and content issues. (Discuss in Talk:BIND#)

BIND (or named) is the most widely used Domain Name System (DNS) server.

Note: The organization developing BIND is serving security notices to paying customers up to four days before Linux distributions or the general public.[1]

Installation

Install the bind package.

Start/enable the named.service systemd unit.

To use the DNS server locally, use the 127.0.0.1 nameserver, see Domain name resolution. This will however require you to #Allow recursion.

Configuration

BIND is configured in /etc/named.conf. The available options are documented in named.conf(5).

Reload the named.service unit to apply configuration changes.

Restrict access to localhost

BIND by defaults listens on all interfaces and IP addresses.

To only allow connections from localhost add the following line to the options section in /etc/named.conf:

listen-on { 127.0.0.1; };

Set up DNS forwarding

To make BIND forward DNS queries to another DNS server add the forwarders clause to the options section.

Example to make BIND forward to the Google DNS servers:

forwarders { 8.8.8.8; 8.8.4.4; };

A configuration template for running a domain

This is a simple tutorial in howto setup a simple home network DNS-server with bind. In our example we use "domain.tld" as our domain.

For a more elaborate example see Two-in-one DNS server with BIND9.

Another guide at Linux Home Server HOWTO - Domain name system (BIND): Adding your domain will show you how to set up internal network name resolution in no time; short, on-point and very informative.

Creating a zonefile

Create /var/named/domain.tld.zone.

$TTL 7200
; domain.tld
@       IN      SOA     ns01.domain.tld. postmaster.domain.tld. (
                                        2007011601 ; Serial
                                        28800      ; Refresh
                                        1800       ; Retry
                                        604800     ; Expire - 1 week
                                        86400 )    ; Minimum
                IN      NS      ns01
                IN      NS      ns02
ns01            IN      A       0.0.0.0
ns02            IN      A       0.0.0.0
localhost       IN      A       127.0.0.1
@               IN      MX 10   mail
imap            IN      CNAME   mail
smtp            IN      CNAME   mail
@               IN      A       0.0.0.0
www             IN      A       0.0.0.0
mail            IN      A       0.0.0.0
@               IN      TXT     "v=spf1 mx"

$TTL defines the default time-to-live in seconds for all record types. In this example it is 2 hours.

Serial must be incremented manually before restarting named every time you change a resource record for the zone. If you forget to do it slaves will not re-transfer the zone: they only do it if the serial is greater than that of the last time they transferred the zone.

Configuring master server

Add your zone to /etc/named.conf:

zone "domain.tld" IN {
        type master;
        file "domain.tld.zone";
        allow-update { none; };
        notify no;
};

Reload the named.service unit to apply the configuration change.

Allow recursion

If you are running your own DNS server, you might as well use it for all DNS lookups. This will require the ability to do recursive lookups. In order to prevent DNS Amplification Attacks, recursion is turned off by default for most resolvers. The default Arch /etc/named.conf file allows for recursion only on the loopback interface:

allow-recursion { 127.0.0.1; };

Tango-inaccurate.pngThe factual accuracy of this article or section is disputed.Tango-inaccurate.png

Reason: LAN networking isn't recursive. (Discuss in Talk:BIND#)

If you want to provide name service for your local network; e.g. 192.168.0.0/24, you must add the appropriate range of IP addresses to /etc/named.conf:

allow-recursion { 192.168.0.0/24; 127.0.0.1; };

Configuring BIND to serve DNSSEC signed zones

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: This is just a list of links. (Discuss in Talk:BIND#)

Automatically listen on new interfaces

By default bind scan for new interfaces and stop listening on interfaces which no longer exist every hours. You can tune this value by adding :

interface-interval <rescan-timeout-in-minutes>;

parameter into named.conf options section. Max value is 28 days. (40320 min)
You can disable this feature by setting its value to 0.

Then restart the service.

Running BIND in a chrooted environment

Running in a chroot environment is not required but improves security.

Creating the Jail House

In order to do this, we first need to create a place to keep the jail, we shall use /srv/named, and then put the required files into the jail.

 mkdir -p /srv/named/{dev,etc,usr/lib/engines,var/{run,log,named}}
 # Copy over required system files
 cp -av /etc/{localtime,named.conf} /srv/named/etc/
 cp -av /usr/lib/engines-1.1/* /srv/named/usr/lib/engines/
 cp -av /var/named/* /srv/named/var/named/.
 # Set up required dev nodes
 mknod /srv/named/dev/null c 1 3
 mknod /srv/named/dev/random c 1 8
 # Set Ownership of the files
 chown -R named:named /srv/named

This should create the required file system for the jail.

Service File

Next we need to create the new service file which will allow force bind into the chroot

 cp -av /usr/lib/systemd/system/named.service /etc/systemd/system/named-chroot.service

we need to edit how the service calls bind.

/etc/systemd/system/named-chroot.service
  ExecStart=/usr/bin/named -4 -f -u named -t "/srv/named"

How, restart the systemd service.

See also