2 linux managing dns servers lpic 2 m2 slides kho tài liệu training

Understanding DNS

Andrew Mallett
@theurbanpenguin | www.theurbanpenguin.com


Overview
•

BIND configuration files

•

Zone files

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Named and rndc

•

Server tools

•

Client tools


$ dpkg -L bind9
/etc/bind/named.conf
/etc/bind/rndc.key

$ named -v | V

Configuration Files
We can use dpkg or rpm to list the package contents


/etc/bind/db.local
/etc/bind/db.127
$GENERATE 10-254 $ PTR dhcp-$.example.com

Zone Files
DNS information is stored in text file called zones. BIND can auto-create entries with
$GENERATE


A chroot jail can protect against malicious attack
The directory named ‘runs from’ appears as the root of
the filesystem
Create directory structure first
Use option -t in /etc/default/bind9


$ sudo -u bind rndc status
$ rndc-confgen
TCP PORT 953

Control DNS Server
The command rndc can be used to control the named service.

$ sudo named-checkconf
$ sudo named-checkzone localhost /etc/bind/db.local

Additional Server Tools
We can run syntax checks on the configuration file and on zones.


$ dig www.pluralsight.com -t A
$ nslookup -query=A www.pluralsight.com

Client Tools
The package dnsutils provides client tools such as dig and nslookup. More on client
tools later.


Summary
•

Identified configuration files

•

Viewed sample zone files

•

•

Confirmed version and status of the
server

Server and client tools


Next Up : Installing BIND on
CentOS 7