Why does hostname --fqdn only return the domain name?

Question

Relevant files (slightly anonymized):

heinzi@d2:~$ cat /etc/hostname
d2
heinzi@d2:~$ cat /etc/hosts
127.0.0.1       localhost
<myexternalip>  d2.<myname>.at    <myname>.<myprovider>.at       <myname>

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

This output is correct:

heinzi@d2:~$ hostname
d2
heinzi@d2:~$ hostname --all-fqdns
d2.<myname>.at

But this I don't understand:

heinzi@d2:~$ hostname --fqdn
<myprovider>.at

Shouldn't it be d2.<myname>.at, since that's the first entry after <myexternalip>? And if it's the second entry, shouldn't it by <myname>.<myprovider>.at instead of just the domain name?

I'm aware that I could probably fix this by playing around with the hosts file, but I'd really like to understand why this happens. I read the hostname man page and googled and think that it should return d2.<myname>.at in my case. Thus, I'd really prefer an answer along the lines of "This is because ..." instead of "Try ... and see if it works.".

The system is Debian 7.5 "wheezy".

Solution

As it turns out, the culprit was /etc/resolv.conf. Changing:

search <myprovider>.at
nameserver ...
nameserver ...
nameserver ...

to

search <myname>.at <myprovider>.at
nameserver ...
nameserver ...
nameserver ...

fixes the issue.

(I'll leave the question open for the time being, just in case someone can come up with an explanation for this.)

Comments

[Tony Anderson]

Instead of using <my name> use the words 'foo' and 'bar', it is easier to read.

[Heinzi]

@spuder: Thanks, I'll keep that in mind for my next question.

[Volker Siegel]

@spuder I see your point, but here, the term Name or Provider in the names are useful. Hmm... maybe you meant replacing <myname> not by foo, but by fooName? That's much better indeed.