upgrade to precise required a change in /etc/network/interfaces

[Marius Gedminas]

On Fri, Jul 20, 2012 at 11:07:52AM +0100, Adam Funk wrote:
> On 2012-07-19, Jared Norris wrote:
> 
> > On 19 July 2012 20:47, Adam Funk <a24061 at ducksburg.com> wrote:
> >> Yesterday I upgraded my home desktop, which has been using a static
> >> LAN IP address for years, to Precise, and it had no DNS after
> >> restarting.  The /etc/network/interfaces file contained this stanza:
> >>
> >> #v+
> >> auto eth0
> >> iface eth0 inet static
> >>       address 192.168.123.4
> >>       netmask 255.255.255.0
> >> #v-
> >>
> >> which had previously worked without any problem.  I figured out after
> >> some fiddling that adding a dns-nameserver line to the stanza made
> >> everything work again.  But I'm curious: why did this upgrade suddenly
> >> require that change?
> 
> > The best explanation I could find was
> > http://www.stgraber.org/2012/02/24/dns-in-ubuntu-12-04/
> 
> Is there any good reason that man 5 interfaces still doesn't mention
> the dns-nameserver option at all?  I had a good idea that this was the
> file I needed to tinker with, but it took me a while to find the magic
> words on the WWW.

I don't know the real reason, but I guess it's because dns-nameserver is
not handled by the ifup infrastructure itself, but rather by one of the
/etc/network/if-up.d/ scripts provided by a different package
(resolvconf?).

The manual page even mentions that explicitly:

    Additional options can be given on subsequent lines in the
    stanza. Which options are available depends on the family
    and method, as described below. Additional options can be
    made available by other Debian packages. For example, the
    wireless-tools package makes available a number of options
    prefixed with "wireless-" which can be used to configure the
    interface using iwconfig(8). (See wireless(7) for details.)

Still, since resolvconf is installed by default on Ubuntu 12.04, and
this option is now apparently necessary to get a fully working static
connection (unless you manually replace the /etc/resolv.conf symlink
with a regular file), I think the manual page should mention the
"dns-" options too, with a reference to resolvconf(8) for details.

Can you file a bug?

Marius Gedminas
-- 
I have yet to see any problem, however complicated, which, when
you looked at it in the right way, did not become still more complicated.
                -- Poul Anderson
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