Re: fqdn, dhclient.conf and networkmanager ?

[Patrik Martinsson <martinsson patrik gmail com>]

On Wed, 2008-11-19 at 15:49 +0100, Patrik.Martinsson wrote:
> 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 ? 
>
> Looks like IPv6, yes, but NM doesn't explicitly do anything with IPv6,
> and there's a completely separate IPv6 DHCP client called dhcp6.  What
> options are you invoking dhclient with manually?  -4 perhaps?

> We may want to force -4 anyway, because we'll have completely separate
> support for IPv6 later using dhcp6.

> Dan

I understand what you say, however im not invoking any options to dhclient, infact i 
did 'ps aux | grep dhclient' when it was started from NetworkManager and copied that
command and ran it which resulted in correct behavior. That is why im so confused
about this whole thing. I dont have a clue why it behaves incorrect when called
from NetworkManager. 

/Patrik 


> 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.