Wednesday, 22 May 2019

DNS configuration for RAC setup 12 R1


(note related to nameserver)
chkconfig iptables off
chkconfig ip6tables off
service iptables stop
service ip6tables stop
vi /etc/selinux/config
change SELinux=enforcing to SELinux=disabled


yum install bind bind-chroot caching-nameserver



:~# chattr +i /etc/resolv.conf (to make permanent entry on resolv.conf entry)
########################################################################
[root@smrprodb1 named]# cat /etc/resolv.conf
# Generated by NetworkManager
search example.com
nameserver srv-scan.example.com
domain example.com
########################################################################
# No nameservers found; try putting DNS servers into your
# ifcfg files in /etc/sysconfig/network-scripts like so:
#
# DNS1=xxx.xxx.xxx.xxx
# DNS2=xxx.xxx.xxx.xxx
# DOMAIN=lab.foo.com bar.foo.com
[root@smrprodb1 named]#
########################################################################

[root@smrprodb1 named]# cat /var/named/chroot/etc/named.conf
//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//

options {
# listen-on port 53 { 127.0.0.1; 20.198.242.116; };
# listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
allow-query { localhost; 20.198.242.0/24; };
recursion yes;

dnssec-enable yes;
dnssec-validation yes;
dnssec-lookaside auto;

/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
};

logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};

zone "example.com" IN {
type master;
file "forward.zone";
};

zone "56.168.192.in-addr.arpa" IN {
type master;
file "reverse.zone";
};
[root@smrprodb1 named]#

###############################################################
[root@smrprodb1 named]# cat forward.zone
; /var/named/chroot/var/named/forward.zone
$TTL 86400
@ IN SOA srv-scan.example.com. root.srv-scan.example.com. (
     0 ; serial
     1D ; refresh
     1H ; retry
     1W ; expire
     3H ) ; minimum
     IN NS srv-scan.example.com.
srv-scan A 192.168.56.91
srv-scan A 192.168.56.92
srv-scan A 192.168.56.93
[root@smrprodb1 named]#

###############################################################
[root@smrprodb1 named]# cat reverse.zone
;  /var/named/chroot/var/named/reverse.zone
$TTL 86400
@ IN SOA srv-scan.example.com. root.srv-scan.example.com. (
    0 ; serial
    1D ; refresh
    1H ; retry
    1W ; expire
    3H ) ; minimum
    NS srv-scan.example.com.
91 PTR srv-scan.example.com.
92 PTR srv-scan.example.com.
93 PTR srv-scan.example.com.
##############################################################
[root@smrprodb1 named]#
[root@smrprodb1 etc]# cat named.rfc1912.zones
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
zone "." IN {
type hint;
file "named.ca";
};
zone "example.com" IN {
type master;
file "forward.zone";
allow-update { none; };
};
zone "localhost" IN {
type master;
file "localhost.zone";
allow-update { none; };
};
zone "56.168.192.in-addr.arpa" IN {
type master;
file "reverse.zone";
allow-update { none; };
};
#zone "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa" IN {
#type master;
#file "named.ip6.local";
#allow-update { none; };
#};
zone "255.in-addr.arpa" IN {
type master;
file "named.broadcast";
allow-update { none; };
};
#zone "0.in-addr.arpa" IN {
#type master;Oracle 11gR2 RAC On VM - INSTALLATION
#www.reachdba.com | www.dbalounge.com | info@dbalounge.com | 011-40581394
#file "named.zero";
#allow-update { none; };
#};
[root@smrprodb1 etc]#


 service named start
 service named status
chkconfig named on

##########################################################################

Hosts entry details

[root@srv1 named]# cat /etc/hosts
127.0.0.1   localhost.localdomain localhost
# Public
192.168.56.71   srv1.example.com        srv1
192.168.56.72   srv2.example.com        srv2

# Private
192.168.10.1    srv1-priv.example.com   srv1-priv
192.168.10.2    srv2-priv.example.com   srv2-priv

# Virtual
192.168.56.81   srv1-vip.example.com    srv1-vip
192.168.56.82   srv2-vip.example.com    srv2-vip

# SCAN (in production this should be configured in DNS)
192.168.56.91   srv-scan.example.com    srv-scan
192.168.56.92   srv-scan.example.com    srv-scan
192.168.56.93   srv-scan.example.com    srv-scan

[root@srv1 named]#

OUTPUT:

[root@srv1 etc]#  nslookup srv-scan
Server:         127.0.0.1
Address:        127.0.0.1#53

Name:   srv-scan.example.com
Address: 192.168.56.92
Name:   srv-scan.example.com
Address: 192.168.56.93
Name:   srv-scan.example.com
Address: 192.168.56.91

[root@srv1 etc]#  nslookup srv-scan
Server:         127.0.0.1
Address:        127.0.0.1#53

Name:   srv-scan.example.com
Address: 192.168.56.93
Name:   srv-scan.example.com
Address: 192.168.56.91
Name:   srv-scan.example.com
Address: 192.168.56.92

[root@srv1 etc]#  nslookup srv-scan
Server:         127.0.0.1
Address:        127.0.0.1#53

Name:   srv-scan.example.com
Address: 192.168.56.91
Name:   srv-scan.example.com
Address: 192.168.56.92
Name:   srv-scan.example.com
Address: 192.168.56.93

[root@srv1 etc]#

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