Tuesday, June 8, 2010

BIND 9 Configure Views To Partition External and Internal DNS Information

SkyHi @ Tuesday, June 08, 2010

How do I configure Bind 9 dns server views to allow a single nameserver in my DMZ to make different sets of data available to different sets of clients? For example, I'd like to run recursion, some other data for LAN users (192.168.1.0/24), and for the Internet user I'd like to display limited DNS data without recursion. How do I configure views to partition external (Internet) and internal (LAN) DNS information?

You need to edit /etc/named.conf or /var/named/chroot/etc/named.conf file, run (the following configuration is tested on FreeBSD and RHEL 5.x BIND 9 servers):
# vi /var/named/chroot/etc/named.conf
Append the following and define internal subnet (192.168.1.0/24 and localhost with full access and recursion):

acl internal {
192.168.1.0/24;
localhost;
};

Define zone and other data as per your requirements:

//
// Lan zone recursion is the default
//
view "internal-view" {
match-clients { internal; };
zone "." IN {
type hint;
file "db.cache";
};
zone "internal.nixcraft.com " IN {
type master;
file "zones/lan.master.nixcraft.com";
allow-transfer { key TRANSFER; };
};
};
//
// external zone w/o recursion
//
view "external-view" {
match-clients { any; };
recursion no;
zone "nixcraft.com " IN {
type master;
file "zones/internet.master.nixcraft.com";
allow-transfer { key TRANSFER; };
};
};

Make sure you configure TSIG as described here.

Create Zone Files

First, create required directories, enter:
# mkdir -p /var/named/chroot/var/named/zones
# chown named:named /var/named/chroot/var/named/zones

Create Internal Zone With LAN IP Data

Edit /var/named/chroot/var/named/zones/lan.master.nixcraft.com, run:
# vi /var/named/chroot/var/named/zones/lan.master.nixcraft.com
Append the data, enter:

$ORIGIN nixcraft.com.
$TTL 3h
@ IN SOA ns1.nixcraft.com. vivek.nixcraft.com. (
20080703328 ; Serial yyyymmddnn
3h ; Refresh After 3 hours
1h ; Retry Retry after 1 hour
1h ; Expire after 1 week 1w
1h) ; Minimum negative caching of 1 hour

@ IN NS ns1.nixcraft.com.
@ IN NS ns2.nixcraft.com.

@ 3600 IN MX 10 mail1.nixcraft.com.
@ 3600 IN MX 20 mail2.nixcraft.com.

@ 3600 IN A 208.43.79.236
ns1 3600 IN A 208.43.138.52
ns2 3600 IN A 75.126.168.152
mail1 3600 IN A 208.43.79.236
mail2 3600 IN A 67.228.49.229
out-router 3600 IN A 208.43.79.100
; lan data
wks1 3600 IN A 192.168.1.5
wks2 3600 IN A 192.168.1.5
wks3 3600 IN A 192.168.1.5
in-router 3600 IN A 192.168.1.254
; add other lan specifc data below

Edit /var/named/chroot/var/named/zones/internet.master.nixcraft.com, run:
# vi /var/named/chroot/var/named/zones/internet.master.nixcraft.com
Same as above but no internal data:

$ORIGIN nixcraft.com.
$TTL 3h
@ IN SOA ns1.nixcraft.com. vivek.nixcraft.com. (
20080703328 ; Serial yyyymmddnn
3h ; Refresh After 3 hours
1h ; Retry Retry after 1 hour
1h ; Expire after 1 week 1w
1h) ; Minimum negative caching of 1 hour

@ IN NS ns1.nixcraft.com.
@ IN NS ns2.nixcraft.com.

@ 3600 IN MX 10 mail1.nixcraft.com.
@ 3600 IN MX 20 mail2.nixcraft.com.

@ 3600 IN A 208.43.79.236
ns1 3600 IN A 208.43.138.52
ns2 3600 IN A 75.126.168.152
mail1 3600 IN A 208.43.79.236
mail2 3600 IN A 67.228.49.229
out-router 3600 IN A 208.43.79.100

Finally, reload data:
# rndc reload
Test it, enter:
$ ping in-router.nixcraft.com
$ ping out-router.nixcraft.com

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