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How to setup dns resolver in Ubunut 12 server ?

My first Precise Pangolin deployment.

I'm having issues with dns resolution not working - turns out /etc/resolv.conf is not anymore the place to manage this.

I tried to add “dns-nameservers”, “dns-search” and “dns-domain” entries in /etc/network/interfaces but they don't seem to work either (no server could be reached error, although I can ping those listed with dns-nameservers.

My interfaces files reads

auto eth0
iface eth0 inet static
address 172.16.200.50
netmask 255.255.255.0
gateway 172.16.200.1
dns-nameservers 172.16.200.25 172.16.100.5
dns-search mydomain.local

If I do a host xxx.domain.com 172.16.200.25 it works - it's just that there is a config problem with default resolvers.

What am I missing ?

Sjizzel

can you please post the contents of your /etc/resolv.conf file?

should be something like

nameserver 172.16.200.25
search mydomain.local

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can you also post the output of the command 'dig'?
should be something like:

; <<>> DiG 9.8.1-P1 <<>>
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55303
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;.                              IN      NS

;; ANSWER SECTION:
.                       2816    IN      NS      f.root-servers.net.
.                       2816    IN      NS      j.root-servers.net.
.                       2816    IN      NS      m.root-servers.net.
.                       2816    IN      NS      e.root-servers.net.
.                       2816    IN      NS      h.root-servers.net.
.                       2816    IN      NS      a.root-servers.net.
.                       2816    IN      NS      c.root-servers.net.
.                       2816    IN      NS      l.root-servers.net.
.                       2816    IN      NS      d.root-servers.net.
.                       2816    IN      NS      g.root-servers.net.
.                       2816    IN      NS      b.root-servers.net.
.                       2816    IN      NS      k.root-servers.net.
.                       2816    IN      NS      i.root-servers.net.

;; Query time: 3 msec
;; SERVER: 172.16.200.25#53(172.16.200.25)
;; WHEN: Thu Aug 16 12:19:16 2012
;; MSG SIZE  rcvd: 228

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Alexandre Takacs

ASKER

The /etc/resolv.conf reads "#DO NOT EDIT THIS FILE" and has one entry "dns-search mydomain.local" (presumably carried over from the interfaces directives).

As for "dig" it times out with an error "no servers could be reached".

legolasthehansy

Wow - They changed the location of the resolvers on Ubuntu?
According to this file, you are right on the money on making changes to /etc/network/interfaces according to this link
http://www.stgraber.org/2012/02/24/dns-in-ubuntu-12-04/

Is your DNS server up?
Can you try putting 8.8.8.8 on this file and see if DNS works first

Alexandre Takacs

ASKER

Yes my DNS are working ok if I specify them in a "host" lookup. Just that somehow - despite my settings above - the system does not seem to know how to resolve by itself. Although a server it does not have BIND installed and don't really plan to.

As an aside what was the rationale behind removing support for /etc/resolv.conf ? I'm sure it's not just to annoy long time users... [Edited: ok I have followed some of the links above and better understand the change although not 100% convinced].

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Alexandre Takacs

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Alexandre Takacs

ASKER

Self solved