making samba internal DNS "site" aware for some queries

[David Mansfield]

When a DNS query for _kerberos._tcp.samdom.example.com (and possibly 
others) is processed by samba4, the answers appear to be in the same 
order regardless of which DC is queried (when internal DNS is used).

It to me that either:

- each DC should put itself first
- the "site" subnets should be consulted based on the requestor's IP 
address and the matching DC should be put first

Why this matters:

If the following fragment is in krb5.conf:

[libdefaults]
     dns_lookup_kdc = true

The client will never use the "closest" DC for kerberos AFAIK (although 
it will for winbind).

So here are questions:

1) is the current behavior expected?
2) is my suggested behavior allowed?
3) is my suggested behavior desirable?
4) what source code would I look at to implement, assuming #2 and #3 are 
both "yes"?

-- 
Thanks,
David Mansfield
Cobite, INC.