DNS error: server can't find server1: SERVFAIL

To learn · 08-23-2016, 12:44 PM

Greetings to all.
I have configured two machines in my network.

1. apple.itssnp.edu.mx (This is my DNS server)
2. www.itssnp.edu.mx (This is my client machine)

When I am running nslookup www I get below error message.

Quote:

[root@apple usuariocc]# nslookup www
Server: 10.10.10.2
Address: 10.10.10.2#53

** server can't find www: SERVFAIL

But when I run nslookup www.itssnp.edu.mx I get correct response.

Quote:

[root@apple usuariocc]# nslookup www.itssnp.edu.mx
Server: 10.10.10.2
Address: 10.10.10.2#53

Name: www.itssnp.edu.mx
Address: 10.10.10.2

Same is applicable with dig command

Quote:

[root@apple usuariocc]# dig www

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6 <<>> www
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 23700
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www. IN A

;; Query time: 35 msec
;; SERVER: 10.10.10.2#53(10.10.10.2)
;; WHEN: Tue Aug 23 10:33:52 2016
;; MSG SIZE rcvd: 21

[root@apple usuariocc]# dig www.itssnp.edu.mx

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6 <<>> www.itssnp.edu.mx
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31083
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;www.itssnp.edu.mx. IN A

;; ANSWER SECTION:
www.itssnp.edu.mx. 86400 IN A 10.10.10.2

;; AUTHORITY SECTION:
itssnp.edu.mx. 86400 IN NS ns2.itssnp.edu.mx.
itssnp.edu.mx. 86400 IN NS ns1.itssnp.edu.mx.

;; ADDITIONAL SECTION:
ns1.itssnp.edu.mx. 86400 IN A 10.10.10.2
ns2.itssnp.edu.mx. 86400 IN A 10.10.10.1

;; Query time: 1 msec
;; SERVER: 10.10.10.2#53(10.10.10.2)
;; WHEN: Tue Aug 23 10:34:33 2016
;; MSG SIZE rcvd: 119

I have below configuration for /etc/named.conf file

Quote:

[root@apple usuariocc]# cat /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 { any; };
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 { any; };
recursion yes;

dnssec-enable yes;
dnssec-validation yes;

/* 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";

};

include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";

zone "itssnp.edu.mx" IN {
type master;
file "itssnp.db";
allow-transfer { 10.10.10.1; };

};

I have below configuration for /var/named/itssnp.db
file

Quote:

[root@apple usuariocc]# cat /var/named/itssnp.db
$TTL 1D
@ IN SOA @ webmaster.itssnp.edu.mx. (
2015030901 ; serial
1H ; refresh
1800 ; retry
1W ; expire
3H ) ; minimum
@ NS ns1
ns1 A 10.10.10.2
@ NS ns2
ns2 A 10.10.10.1

www A 10.10.10.2
apple A 10.10.10.2

bathory · 08-23-2016, 03:24 PM

Hi,

Check for a search (or domain) line in /etc/resolv.conf.
If there is one, nslookup automatically appends that domain to the query, so perhaps there is a misconfigured domain in /etc/resolv.conf.

On the other hand for dig, you should add the "+search" option in order to add the domain from /etc/resolv.conf to the query name

Code:

dig www +search

I don't know why you get a SERVFAIL running dig, instead of a NXDOMAIN

BTW apple has the same IP as www in the zonefile posted. Are you sure it's correct?

To learn · 08-29-2016, 11:58 AM

Thanks

That worked perfectly