How to correctly specify the DNS server for Ubuntu?

Question

Domain Name System

Hello everyone, I installed the Zimbra mail server on the local network and the web interface and admin panel work, but when sending a letter they get into the queue and are not sent with the error "Host or domain name not found. name service error for name=mail.pk type=a: host not found, try again (1 messages)". I have a bind9 DNS server on my network with the configuration

db.70

;
; BIND reverse data file for local loopback interface
;
$TTL 604800
@ IN SOA sambajabber.pk. root.sambajabber.pk. (
2017080200 ; Serial
604800 ; Refresh
86400 ; Retry
2419200 ; Expire
604800 ) ; Negative Cache TTL
;
@ IN NS sambajabber.
80 IN PTR sambajabber.pk.
81 IN PTR mail.pk.
37 IN PTR mail2.pk.

db.pk

$TTL 86400
@ IN SOA sambajabber.pk. root.pk. (
2017070600 ;Serial
604800 ;Refresh
86400 ;Retry
2419200 ;Expire
86400) ;Nagative Cache TTL
;
@ IN NS sambajabber.pk.
sambajabber IN A 70.71.72.80
* IN CNAME @
mail IN A 70.71.72.81
@ IN MX 10 mail.pk.
mail2 IN A 70.71.72.37
@ IN MX 20 mail2.pk.

And there is also an Axigen server that works in full. Those. the problem is in the machine on which Zimbra is installed.

ifconfig

[email protected]:~$ ifconfig
eth0 Link encap:Ethernet HWaddr 00:15:5d:48:21:16
inet addr:70.71.72.37 Bcast:70.71.72.255 Mask:255.255.255.0
inet6 addr: fe80::215:5dff:fe48:2116/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:4831 errors:0 dropped:0 overruns:0 frame:0
TX packets:5461 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:924436 (924.4 KB) TX bytes:5950571 (5.9 MB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:11140 errors:0 dropped:0 overruns:0 frame:0
TX packets:11140 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:12212922 (12.2 MB) TX bytes:12212922 (12.2 MB)

hosts

127.0.0.1 localhost
70.71.72.37 mail2.pk mail2
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback localhost
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

resolv.conf

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1
search pk

/etc/hostname

mail2.pk

/etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto eth0
iface eth0 inet static
address 70.71.72.37
netmask 255.255.255.0
network 70.71.72.0
broadcast 70.71.72.255
gateway 70.71.72.1
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 70.71.72.80
dns-search pk

This machine does not ping other machines on the network by their dns name. Those. crooked DNS, but everything is configured in the interfaces, why is DNS not working? and how to correctly specify the server address?

Answer 1

to register in /etc/resolvconf/resolv.conf.d/base the correct address of the dns-server
nameserver 70.71.72.80
??
although dns-nameservers 70.71.72.80 from interfaces should be copied to resolv.conf