samba - Oct 2014 - Client drops off Active Directory when DC changes its IP

Hi all,
I have a Linux webserver VM running in a windows network. It's accessible
via http://hostname on our intranet. Our DC is a Windows server (I think a
2008 R2 box).  Now, for the most part, this works pretty good. But it's
unreliable.

Every so often, it seems the Linux client drops off the network. I find
that the DC is every so often changing the IP address of the client. The
webserver no longer serves pages at http://hostname, but I can still ssh
into it from another linux box via host. Apparently this is common, but I
can't get the client to respond to that and auto correct itself. I have to
manually fix this by:

Having IT remove the DNS entry from the DC
stopping smbd, nmbd and winbindd
getting a new kerbos ticket with an admin account
restarting smbd, nmbd and windbindd
joining the domain with an admin account
restarting httpd

This works, but being a webserver, i need it to be self sustained. I'm
pretty sure samba does this, I just don't know how.

I found samba_dnsupdate, but i can't get it to run. it fails with:

Traceback (most recent call last):
  File "/usr/bin/samba_dnsupdate", line 457, in <module>
    sub_vars = get_subst_vars(samdb)
  File "/usr/bin/samba_dnsupdate", line 271, in get_subst_vars
    vars['HOSTNAME']  = samdb.host_dns_name()
  File "/usr/lib/python2.7/site-packages/samba/samdb.py", line 619, in
host_dns_name
    res = self.search(base='', scope=ldb.SCOPE_BASE,
attrs=['dNSHostName'])
_ldb.LdbError: (34, 'NULL Base DN invalid for a base search')


My smb.conf is http://pastebin.com/Rp9rQnPm
my krb5.conf is http://pastebin.com/vR457pvb
the setup instructions i followed were
https://wiki.archlinux.org/index.php/Active_Directory_Integration
which got me about 90% of the way.

let me know what else I can provide,
Thanks,
-- 
Shawn Sullivan
Shelbydz at gmail.com