Setup Master-Slave DNS Server Using “Bind” Tools in RHEL/CentOS 6.5

Domain Name Server (DNS) used for name resolving to any hosts. Master DNS servers (Primary Server) are the original zone data handlers and Slave DNS server (Secondary Server) are just a backup servers which is used to copy the same zone information’s from the master servers. Master Server will resolve the names for every hosts which we defined in the zone database and use UDP protocol, because UDP protocols never use the acknowledgement process while tcp uses acknowledgement. DNS servers also use UDP protocols to resolve the query request at the earliest.

Setup Master Slave DNS in CentOS

Setup Master Slave DNS in RHEL/CentOS 6.5

How DNS Works?

Understanding DNS might be little confusing for newbies. Here is a brief explanation on how the DNS work’s.

Let’s say, if we need to access any website what we will do? Just type www.google.com in browser and hit enter. Hmm that’s all we know, but the fact is, how pain DNS go through it, while querying for us. While we type www.google.com the system will look for www.google.com. Whenever we type some domain name, there is a . (dot) at the end of the www.google.com that say to search the root server of namespace.

Globally there are 13 root servers available to resolve the query. At first, while we hit enter as www.google.com our browser will pass a request to our local resolver, which has entry about our master and slave DNS server info. If they don’t have info about such requested query they will pass the request to the Top Level domain (TLD), if TLD say I don’t know the request, may be the authoritative server know your request, it will forward to authoritative servers, here only www.google.com was defined as address 72.36.15.56.

In mean time authoritative server will give the answer to TLD and TLD will pass to root server and root will provide the info to browser, hence the browser will cache the DNS request for future use. Thus these long process will just resolve with in milliseconds. If they don’t know the request they will reply as NXDOMAIN. That means, there is no record any-were found in the Zone database. Hope this makes you to understand how the DNS works.

Read Also: Setup DNS Cache Server in Ubuntu

My Testing Environment

For this article, I’m using 3 machines, 2 for server setup (master and slave) and 1 for client.

---------------------------------------------------
Master DNS Server
---------------------------------------------------

IP Address	:	192.168.0.200
Host-name	:	masterdns.tecmintlocal.com
OS		:	Centos 6.5 Final
---------------------------------------------------
Slave DNS Server
---------------------------------------------------

IP Address	:	192.168.0.201
Host-name	:	slavedns.tecmintlocal.com
OS		:	Centos 6.5 Final
---------------------------------------------------
Client Machine to use DNS
---------------------------------------------------

IP Address	:	192.168.0.210
Host-name	:	node1.tecmintlocal.com
OS		:	Centos 6.5 Final
Requirement Packages
bind, bind-utils, bind-chroot
Configuration Files Used
config file	:	/etc/named.conf
script file	:	/etc/init.d/named
Port & Protocols Used
53, UDP

Setup Master DNS Server

First, verify the IP address, Hostname and Distribution version of Master DNS Server, before moving forward for setup.

$ sudo ifconfig | grep inet
$ hostname
$ cat /etc/redhat-release
Verify Master Configuration

Verify Master Configuration

Once, you confirm that the above settings are correct, its time to move forward to install required packages.

$ sudo yum install bind* -y
Install Bind Package

Install Bind Package

Installing and Configuring Bind

After installing required packages, now define zone files in master configuration ‘named.conf‘ file.

$ sudo vim /etc/named.conf

Given below is my named.conf file entry, change the configuration file as per your need.

//
// 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; 192.168.0.200; }; # Here we need to add our Master DNS Server IP.
        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; 192.168.0.0/24; }; # subnet range where my hosts are allowed to query our DNS.
        allow-transfer     { localhost; 192.168.0.201; };  # Here we need to our Slave DNS server IP.
        recursion no;

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

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

        managed-keys-directory "/var/named/dynamic";
};

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

zone "." IN {
        type hint;
        file "named.ca";
};

## Define our forward & reverse Zone file here for tecmintlocal.com.


zone"tecmintlocal.com" IN {
type master;
file "tecmintlocal.fwd.zone";
allow-update { none; };
};

zone"0.168.192.in-addr.arpa" IN {
type master;
file "tecmintlocal.rev.zone";
allow-update { none; };
};

#####
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";
Create Zone File in DNS

Create Zone File in DNS

Following are the explanation of each configuration we used in above file.

  1. listen-on port 53 – This is used for the DNS to listen in available interfaces.
  2. Master DNS – Define, your Master DNS IP address to listen the query.
  3. Slave DNS – Define your Slave DNS, which is used to sync our zone information to resolve the hosts from Master.
  4. recursion no – If its set to yes, recursive queries will make the server into DDOS attack.
  5. Zone Name – Define your Zone name here defined as tecminlocal.com.
  6. type master – As this system was configured for a master server, for upcoming slave server this will be slave.
  7. tecmintlocal.fwd.zone – This file have the host information for this zone.
  8. allow-update none – If none will set. it won’t use Dynamic DNS (DDNS).

Creating Master Zone Files

At first let us define forward look-up zone entry. Here we need to create the zone files in the name of what we have define in the named.conf file as below.

tecmintlocal.fwd.zone
tecmintlocal.rev.zone

We use sample configuration files for creating forward zone files, for this we’ve to copy the sample configuration files.

$ sudo cp /var/named/named.localhost /var/named/tecmintlocal.fwd.zone
$ sudo cp /var/named/named.loopback /var/named/tecmintlocal.rev.zone
Copy Zone Files

Copy Zone Files

Once, you’ve copied configuration files, now edit these zones files using vim editor.

$ sudo vim /var/named/tecmintlocal.fwd.zone

Before defining our host information in forward zone file, first have a quick look at the sample zone file.

Sample Zone File

Sample Zone File

This is my forward zone configuration, append the below entry and make changes as per your need.

$TTL 86400
@       IN SOA  masterdns.tecmintlocal.com.     root.tecmintlocal.com. (
                                  2014090401    ; serial
                                        3600    ; refresh
                                        1800    ; retry
                                      604800    ; expire
                                       86400 )  ; minimum

; Name server's

@       IN      NS      masterdns.tecmintlocal.com.
@       IN      NS      slavedns.tecmintlocal.com.

; Name server hostname to IP resolve.

@       IN      A       192.168.0.200
@       IN      A       192.168.0.201

; Hosts in this Domain

@       IN      A       192.168.0.210
@       IN      A       192.168.0.220
masterdns       IN      A       192.168.0.200
slavedns        IN      A       192.168.0.201
node1           IN      A       192.168.0.210
rhel1           IN      A       192.168.0.220

Save and quit the file using wq!. After editing the forward look-up, it looks like below, Use TAB to get a decent format in zone file.

Configure Forward Zone

Configure Forward Zone

Now, create reverse lookup file, we have already made a copy of loop-back file in the name of tecmintlocal.rev.zone. So, we use this file to configure our reverse look-up.

$ sudo vim /var/named/tecmintlocal.rev.zone

Before defining our host information in reverse zone file, have a quick look of sample reverse lookup file as shown below.

Sample Reverse Lookup Zone

Sample Reverse Lookup Zone

This is my reverse zone configuration, append the below entry and make changes as your need.

$TTL 86400
@       IN SOA  masterdns.tecmintlocal.com. root.tecmintlocal.com. (
                                2014090402      ; serial
                                      3600      ; refresh
                                      1800      ; retry
                                    604800      ; expire
                                     86400 )    ; minimum

; Name server's

@       IN      NS      masterdns.tecmintlocal.com.
@       IN      NS      slavedns.tecmintlocal.com.
@       IN      PTR     tecmintlocal.com.

; Name server hostname to IP resolve.

masterdns       IN      A       192.168.0.200
slavedns        IN      A       192.168.0.201

;Hosts in Domain 

node1           IN      A       192.168.0.210
rhel            IN      A       192.168.0.220
200             IN      PTR     masterdns.tecmintlocal.com.
201             IN      PTR     slavedns.tecmintlocal.com.
210             IN      PTR     node1.tecmintlocal.com.
220             IN      PTR     rhel1.tecmintlocal.com.

Save and quit the file using wq!. After editing the reverse look-up, it looks like below, Use TAB to get a decent format in zone file.

Configure Reverse Lookup Zone

Configure Reverse Lookup Zone

Check the group ownership of forward look-up & reverse look-up files, before checking for any errors in configuration.

$ sudo ls -l /var/named/

Here we can see both the files are in root users ownership, because files which we makes a copy from sample files are available under /var/named/. Change the group to named on both files using following commands.

$ sudo chgrp named /var/named/tecmintlocal.fwd.zone
$ sudo chgrp named /var/named/tecmintlocal.rev.zone

After setting correct ownership on the files, verify them again.

$ sudo ls -l /var/named/
Verify Zone Files

Verify Zone Files

Now, check for the errors in zone files, before starting the DNS service. First check the named.conf file, then check other zone files.

$ sudo named-checkconf /etc/named.conf
$ sudo named-checkzone masterdns.tecminlocal.com /var/named/tecmintlocal.fwd.zone
$ sudo named-checkzone masterdns.tecminlocal.com /var/named/tecmintlocal.rev.zone
Check Errors Zone Files

Check Errors Zone Files

By default iptables was running and our DNS server is restricted to localhost, if client wants to resolve name from our DNS Server, then we have to allow the inbound request, for that we need to add iptables inbound rule for the port 53.

$ sudo iptables -I INPUT -p udp --dport 53 -m state --state NEW -j ACCEPT

Now, verify that the rules has been added correctly in INPUT chain.

$ sudo iptables -L INPUT

Next, save the rules and restart firewall.

$ sudo service iptables save
$ sudo service iptables restart
Open DNS Port on Firewall

Open DNS Port on Firewall

Start the named service and make it persistent.

$ sudo service named start
$ sudo chkconfig named on
$ sudo chkconfig --list named
Start DNS Server

Start DNS Server

Finally, test the configured Master DNS zone files (forward and reverse), using dig & nslookup tools.

$ dig masterdns.tecmintlocal.com		[Forward Zone]
Test Forward DNS Zone

Test Forward DNS Zone

$ dig -x 192.168.0.200
Test Reverse DNS Zone

Test Reverse DNS Zone

$ nslookup tecmintlocal.com
$ nslookup masterdns.tecmintlocal.com
$ nslookup slavedns.tecmintlocal.com
Test DNS Zones

Test DNS Zones

Cool! we have configured a Master DNS, now we need to setup a Slave DNS Server. Let’s move forward to setup a slave server, This won’t take much time as master setup.

Setup Slave DNS Server

In Slave machine, also we need to install same bind packages as shown in Master, so let’s install them using following command.

$ sudo yum install bind* -y
Install DNS Bind in CentOS

Install DNS Bind

Open and edit ‘named.conf’ file for our zone database and port listen.

$ sudo vim /etc/named.conf

Make changes as shown, as per your requirements.

//
// 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; 192.168.0.201}; # Our Slave DNS server IP
        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; 192.168.0.0/24; };
        recursion no;

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

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

        managed-keys-directory "/var/named/dynamic";
};

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

zone "." IN {
        type hint;
        file "named.ca";
};

## Define our slave forward and reverse zone, Zone files are replicated from master.

zone"tecmintlocal.com" IN {
type slave;
file "slaves/tecmintlocal.fwd.zone";
masters { 192.168.0.200; };
};

zone"0.168.192.in-addr.arpa" IN {
type slave;
file "slaves/tecmintlocal.rev.zone";
masters { 192.168.0.200; };
};

#####
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";
Configure Slave DNS

Configure Slave DNS

Start the DNS service using.

$ sudo service named start

After restarting the bind service, we don’t have to define the zone information individually, as our allow-transfer will replicate the zone information from master server as shown in the image below.

$ sudo ls -l /var/named/slaves

Verify, the zone information using cat command.

$ sudo cat /var/named/slaves/tecmintlocal.fwd.zone
$ sudo cat /var/named/slaves/tecmintlocal.rev.zone
Verify Slave Zone Files

Verify Slave Zone Files

Next, open DNS port 53 on iptables to allow inbound connection.

$ sudo iptables -I INPUT -p udp --dport 53 -m state --state NEW -j ACCEPT

Save the iptables rules and restart the iptables service.

$ sudo service iptables save
$ sudo service iptables restart

Make the service persistent on system boot.

$ sudo chkconfig iptables on
Check whether persistent set for run-levels .
$ sudo chkconfig --list iptables
Open DNS Port

Open DNS Port

That’s it!. Now time to configure our client machines and check for the hostname.

Configure Client Machine

In client side we need to assign the Primary (192.168.0.200) and Secondary DNS (192.168.0.201) entry in network settings to get assign a hostname. To do, run the setup command to define all these entries as shown in the picture.

$ setup
Add DNS Entry

Add DNS Entry

Else, edit the ‘/etc/reslov.conf‘ file and add the following entries.

$ vim /etc/resolv.conf
search tecmintlocal.com
nameserver 192.168.0.200
nameserver 192.168.0.201

Now, verify the ip, hostname and name server look-up.

$ ifconfig | grep inet
$ hostname
$ nslookup tecmintlocal.com
Verify DNS Entry

Verify DNS Entry

Now, check the forward & Reverse DNS look-up using.

$ dig masterdns.tecmintlocal.com
$ dig -x 192.168.0.200
Check DNS Info

Check DNS Info

Understaing the dig Output:

  1. Header – This says everything what we have asked and how the result was.
  2. Status – Status was NO ERROR, that means which query request sent by us was successful without any ERROR.
  3. Question – The Query which was made by us, here my query was masterdns.tecmintlocal.com.
  4. Answer – The Query request resolved if there is available information.
  5. Authority – The name servers response for the domain and zone.
  6. Additional – Additional info’s regarding name-servers such as host-name and IP address.
  7. Query time – How long it took for resolving the names from the above servers.

Finally check for our node and make a ping.

$ dig node1.tecmintlocal.com
Check Client DNS Info

Check Client DNS Info

$ ping masterdns.tecmintlocal.com -c 2
$ ping slavedns.tecmintlocal.com -c 2
$ ping 192.168.0.200 -c 2
$ ping 192.168.0.201 -c 2
Ping DNS Servers

Ping DNS Servers

Finally, setup completed, here we have configured both Primary (Master) and Slave (Seconday) DNS server successfully, hope everyone have setup-ed without any issue, feel free to drop a comment if you face any issue while setup.

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83 Responses

  1. Krishna says:

    if suddenly primary DNS fails what will happen?
    can you please explain the other dns zones like stub zone
    can we configure the stubzone in linux

  2. Husain says:

    Hi Ravi,

    Thanks! for such a informative article. I actually When i am checking reverse lookup zone file. i am getting below error …could you please help me out.

    [[email protected] ~]# named-checkzone vxvm1.husain.net /var/named/husain.rev.zone
    

    zone vxvm1.husain.net/IN: NS ‘vxvm1.husain.net’ has no address records (A or AAAA)
    zone vxvm1.husain.net/IN: not loaded due to errors.

    • @Husain,

      Provide us you configuration in any pastebin or screenshot.

      • Husain says:

        1 $TTL 86400
        2 @ IN SOA vxvm1.husain.net. root.husain.net. (
        3 2014090402 ; serial
        4 3600 ; refresh
        5 1800 ; retry
        6 604800 ; expire
        7 86400 ) ; minimum
        8 ; Name server’s
        9
        10 @ IN NS vxvm1.husain.net.
        11 @ IN NS rhel7.husain.net.
        12 @ IN PTR husain.net.
        13 ; Name server hostname to IP resolve.
        14
        15 vxvm1 IN A 10.10.104.20
        16 rhel7 IN A 10.10.104.115
        17
        18 ;Hosts in Domain
        19 vxvm2 IN A 10.10.104.30
        20 sarvar IN A 10.10.104.111
        21 111 IN PTR sarvar.husain.net.
        22 30 IN PTR vxvm2.husain.net.

  3. raaz says:

    1 $TTL 86400
    2 @ IN SOA ns1.mailninja.io. root.mailninja.io. (
    3 2016090101 ; serial
    4 3600 ; refresh
    5 1800 ; retry
    6 604800 ; expire
    7 86400 ) ; minimum
    8 @ IN NS ns1.mailninja.io.
    9 @ IN NS ns2.mailninja.io.
    10 @ IN PTR mailninja.io.
    11 ns1 IN A 192.168.1.126
    12 ns2 IN A 192.168.1.121
    13 ;Hosts in domain
    14 126 IN PTR ns1.mailninja.io.
    15 121 IN PTR ns2.mailninja.io.

    named-checkzone ns1.mailninja.io /var/named/mailninja.rev.zone
    zone ns1.mailninja.io/IN: NS ‘ns1.mailninja.io’ has no address records (A or AAAA)
    zone ns1.mailninja.io/IN: not loaded due to errors.

    Hi ravi can you plz ellaborate what did i miss here that i am getting errors for reverse zone file.

  4. raaz says:

    named-checkzone ns1.mailninja.io /var/named/mailninja.rev.zone
    zone ns1.mailninja.io/IN: NS ‘ns1.mailninja.io’ has no address records (A or AAAA)
    zone ns1.mailninja.io/IN: not loaded due to errors.

    cat -n 1 $TTL 86400
    2 @ IN SOA ns1.mailninja.io. root.mailninja.io. (
    3 2016090101 ; serial
    4 3600 ; refresh
    5 1800 ; retry
    6 604800 ; expire
    7 86400 ) ; minimum
    8 @ IN NS ns1.mailninja.io.
    9 @ IN NS ns2.mailninja.io.
    10 @ IN PTR mailninja.io.
    11 ns1 IN A 64.137.226.126
    12 ns2 IN A 64.137.167.121
    13 ;Hosts in domain
    14 126 IN PTR ns1.mailninja.io.
    15 121 IN PTR ns2.mailninja.io.

  5. vishant says:

    Starting named:
    Error in named configuration:
    dns_rdata_fromtext: forward:8: near ‘epsilon.jhilmil.com’: extra input text
    zone jhilmil.com/IN: loading from master file forward failed: extra input text
    zone jhilmil.com/IN: not loaded due to errors.
    _default/jhilmil.com/IN: extra input text
    zone localhost/IN: loaded serial 0
    zone 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa/IN: loaded serial 0
    dns_rdata_fromtext: reverse:8: near ‘epsilon.jhilmil.com’: extra input text
    zone 211.168.192.in-addr.arpa/IN: loading from master file reverse failed: extra input text
    zone 211.168.192.in-addr.arpa/IN: not loaded due to errors.
    _default/211.168.192.in-addr.arpa/IN: extra input text
    zone 0.in-addr.arpa/IN: loaded serial 0

    getting this error when starting dns service
    help me out.

  6. Mallikarjunn says:

    Hello Ravi,

    FOR example I have typed dig facebook.com, ok.

    It gives me some dns detials,

    Queston: for ex : I don’t have facebook nameserver address in my local sysem /etc/resolv.conf,?

    so how it gives me the some dns result.

    and

    one more question is very simple.

    I have made one dns server how it goes to public they don’t have my dns server details. how they can see?

    Please clarify my doughts as soon as possible.

    • Aaron Kili K says:

      @Mallikarjunn

      First question:

      When your machine(client) is connected to the Internet through an ISP, it initiates a query to find facebook.com and sends the query to the DNS server of the ISP.

      Then, the DNS Server of the ISP first checks it’s own cache to determine if it already has a result for your machine’s query.

      In the event that the result is negative(meaning nothing found), it generates another query, sends it to a hierarchy above it. Your machine’s query will keep moving up the up until it reaches the root DNS servers, and until when facebook.com is found.

      After the ISP DNS Server finding out the authoritative name servers, it contacts the authoritative name servers to find out the IP address for http://www.facebook.com. i.e. the IP address of host www in the domain facebook.com.

      facebook.com then responds to the ISP DNS Server by answering the query and providing the IP address of the web server i.e. www

      The ISP DNS Server stores the answer in it’s cache for any future use and provides the result to your machine(client) by sending the IP address of the www server plus so many other details.

      Second question:

      All the magic happens through your ISP, when your are connected to the Internet, the ISP must gather information about your network setup including the DNS server setup. Then other networks can find your DNS server through your ISP servers(network).

  7. Mallikarjunn says:

    hi, ravi,

    I don’t understand, how dns works What you have disscussed somewhat tough to understand.

    Please explain in one sentence

    • Ravi Saive says:

      @Mallik,

      We’ve tried and kept the information as simple as it, but I am afraid that you still finding it tough to understand, no problem here is the screencast that tells how exactly dns works, just go through it: https://howdns.works/

  8. arun natarajan says:

    hi babin,

    your post looks great with clear explanation and with color highlights.

    when am configure only master DNS in my machine, facing issue with rev.zone file.

    named.conf testing went fine
    fwd.zone testing went fine.
    rev.zone testing ended with following error.

    [[email protected] ~]# named-checkzone server.example.com /var/named/example.rev.zone
    zone server.example.com/IN: NS ‘server.example.com’ has no address records (A or AAAA)
    zone server.example.com/IN: not loaded due to errors.
    [[email protected] ~]#

    this is my rev zone file.

    [[email protected] ~]# cat /var/named/example.rev.zone
    $TTL 86400
    @ IN SOA server.example.com. root.example.com. (
    0 ; serial
    1D ; refresh
    1H ; retry
    1W ; expire
    3H ) ; minimum
    ;name servers

    @ IN NS server.example.com.
    @ IN PTR example.com.

    ;name server hostname to ip resolver

    server IN A 192.168.1.1
    1 IN PTR server.example.com.

    • Ravi Saive says:

      @Arun,

      I think you should add ‘A’ record pointing to IP address like:

      servername     IN   A       ipaddress
      
      • arun natarajan says:

        that entry is already there ravi…

        FYR

        [[email protected] named]# cat -n example.rev.zone
        1 $TTL 86400
        2 @ IN SOA server.example.com. root.example.com. (
        3 200102 ; serial
        4 3600 ; refresh
        5 1800 ; retry
        6 604800 ; expire
        7 86400 ; minimum )
        8 ;name servers
        9
        10 @ IN NS server.example.com.
        11 @ IN PTR example.com.
        12
        13 ;name server hostname to ip resolver
        14
        15 server IN A 192.168.1.1
        16 1 IN PTR server.example.com.
        17

      • arun natarajan says:

        hi ravi,

        i got the o/p now. thanks for your help and time.

        all verification cmds are giving o/ps expect from below….when diagnosing with ip address

        [[email protected] etc]# dig -x 192.168.1.1

        ; <> DiG 9.7.0-P2-RedHat-9.7.0-5.P2.el6 <> -x 192.168.1.1
        ;; global options: +cmd
        ;; Got answer:
        ;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 48244
        ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
        ;; WARNING: recursion requested but not available

        ;; QUESTION SECTION:
        ;1.1.168.192.in-addr.arpa. IN PTR

        ;; Query time: 0 msec
        ;; SERVER: 192.168.1.1#53(192.168.1.1)
        ;; WHEN: Thu May 26 22:21:38 2016
        ;; MSG SIZE rcvd: 42

        [[email protected] etc]#

  9. shasha says:

    Error: bind97-libs conflicts with bind-libs
    Error: bind97-devel conflicts with bind-libbind-devel
    Error: bind97-chroot conflicts with bind-chroot
    Error: bind97-utils conflicts with bind-utils
    Error: bind97 conflicts with bind
    Error: bind97-devel conflicts with bind-devel

    How to resolve it this error

  10. krishna says:

    THANKS FOR YOUR QUICK RESPONSE, but my question is why we have to write A records in reverse lookup zone
    node1 IN A 192.168.0.210
    rhel IN A 192.168.0.220
    in reverse lookup zone

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