Help writing new SAMBA_INTERNAL DNS test code please.

[Matt Grant]

Hi Andrew!

Have not created Samba bugs for the following yet, as I am trying to get
the hardest part doen, writing the test code.

   1. Dns server port number specification for smb.conf 'dns forwarder'
   server list
   2. Restricting the dynamic DNS update ranges so that the SAMBA_INTERNAL
   server is not spammed with IPv6 PD addresses from the ISP.

Main issue is being able to dynamically change the smb.conf setup for the
Python self test hookup, for 1, specifically within
samba.tests.dns_forwarder.  Being able to do this will also make 2 far
easier.  After looking at the test code set up, I can't see how to
dynamically change the smb.conf file in st/samba/smb.conf while the tests
are running to set up for testing the port numbers or not.

Would specifying a 3rd and 4th 'dns forwarder' entry be possible?  I just
don't want to up set the already written tests.

Best Regards,

Matt Grant