Re: fqdn, dhclient.conf and networkmanager ?

["Patrik.Martinsson" <Patrik Martinsson smhi se>]

On Tue, 2008-11-18 at 11:08 -0500, Dan Williams wrote:
> On Tue, 2008-11-18 at 10:25 +0100, Patrik.Martinsson wrote:
> > Hello all !
> > 
> > I have a question regarding using NetworkManager and dhclient.conf, 
> > maybe i don't understand this right, but however. 
> > 
> > I would like to use NetworkManager but it seems like im not able to
> > apply the same commands to the dhcp server as with dhclient, is
> > NetworkManager using dhclient or does it gets its ip in some other
> > way ? 
> > 
> > I need the same behavior with NetworkManager as a have with dhclient,
> > regarding the options for dynamic update. This is how my dhclient.conf
> > looks today, and i need Networkmanagar to act the same, 
> > 
> > send fqdn.fqdn "hostname.";
> > send fqdn.encoded off;
> > send fqdn.server-update off;
> > append domain-search "foo.bar.com","foo2.bar.com";
> 
> domain-search can be configured in the 'searches' option in the UI,
> either with static or "Automatic (addresses only)".
> 
> So does the DHCP server no honor the send-hostname directive?  That may
> be a Microsoft DNS only option, but I was under the impression that the
> ISC dhcp server supported that as well.
> 
> If not, maybe we need to send the other 3 as well, though the comment in
> 'man dhclient.conf' about encoded on/off doesn't sound very promising.
> 
> In the end, you should be able to put these options
> in /etc/dhclient-eth0.conf (or whatever the interface name is) and have
> them merged in by NetworkManager.
> 
> Dan

Hello, again !

I've spent almost 2 days on this particular problem now, and come up
with some conclusions about whats going on and why it's not behaving
like i want it to. 

I take this from beginning again shortly, just so we are on the same
side here. 
My problem is that, when i manually run dhclient from commandline, my
dns server gets updated, BUT when dhclient is invoked from
NetworkManager, my dns server DON'T get updated. 

First i thought the problem was that the fqdn options that I've
specified in my dhclient.conf didn't get to the dhclient when it was
invoked by the NetworkManager, this is, (of course i realize now in
after-hand) totally wrong.

It doesn't matter if we call it from commandline or trough
NetworkManager, the 
DHCPDISCOVER
DHCPOFFER,
DHCPREQUEST
DHCPACK 
packages looks EXACTLY the same (not timestamps of course, but the
relevant information). Ive checked this with wireshark and compared the
different results with vimdiff. 
They are the same ! Cool, at least the problem isn't there. 

However the problem comes after it gets its DHCPACK, when i call
dhclient from the commandline this gets done, logs from wireshark
---------------------------------------------------------------------
Source      Destination  Protocol Info
XX.XX.X.XX  XXX.XX.X.XX  DNS      Standard query SOA myhostname.foo.bar

Source      Destination  Protocol Info
XXX.XX.X.XX XX.XX.X.XX   DNS      Standard query response

Source      Destination  Protocol Info
XX.XX.X.XX  XXX.XX.X.XX  DNS      Standard query NS foo.bar

Source      Destination  Protocol Info
XXX.XX.X.XX XX.XX.X.XX   DNS      Standard query response NS
dns1.foo.bar dns2.foo.bar dns3.foo.bar 

Source      Destination  Protocol Info
XX.XX.X.XX  XXX.XX.X.XX  DNS      Dynamic update SOA foo.bar
----------------------------------------------------------------------
and my dns, as i stated earlier gets updated correctly. 


BUT, if invoked from the NetworkManager, this is what gets done, 
----------------------------------------------------------------------
Source      Destination  Protocol Info
XX.XX.X.XX  XXX.XX.X.XX  DNS      Standard query AAAA dns3.foo.bar

Source      Destination  Protocol Info
XXX.XX.X.XX XX.XX.X.XX   DNS      Standard query response

Source      Destination  Protocol Info
XX.XX.X.XX  XXX.XX.X.XX  DNS      Standard query AAAA
dns3.foo.bar.foo.bar (No typo here) 

Source      Destination  Protocol Info
XXX.XX.X.XX XX.XX.X.XX   DNS      Standard query response, No such name
-----------------------------------------------------------------------
And this is not right. For some reason it tries with some IPV6 query's?
and everything gets wrong, if i understand these logs right ? 

Ive followed what i found about turning IPV6 off, i don't have such a
interface, modules aren't loaded and i have this in
my /etc/syconfig/network 
NETWORK_IPV6=NO 
and in my /etc/sysconfig/network-scritps/ifcfg-eth0
IPV6INIT=no
IPV6_AUTOCONF=no

NetworkManager does something with something to make it behave like
this, i have no idea why IPV6 is in the picture. 
Or maybe I'm totally off here ? What do guys think ? 

Ive looked around a bit and found this document about IPV6
http://v6fix.net/docs/wide-draft-v6fix.en
where they quite in the beginning have an intersting point that could
have something to do with this. 

1.2.1 Looking up DNS with a given name

    When an application can use both IPv4 and IPv6, it should resolve
    both A RR and AAAA RR with a given name.

    A mis-implemented resolver resolves AAAA RR even if IPv6 is not
    available. (Since IPv6 cannot be used, the resolution of AAAA RR is
    wasting. Also it gives chances to make mistakes to applications.)

    The cause of this problem can be found in the DNS server side. For
    instance, when a query of AAAA RR is received, the DNS server
    replies with a wrong answer.



Any suggestions, tips, advices are welcome, I'm really trying to figure
this out. 

Best regards,
Patrik Martinsson, Sweden.