samba - Sep 2014 - Forward lookup DNS Issues samba 4.1.12-9 el6

Hi guys,

I know this sounds vague and I'll try to explain in more depth now,
but firstly, does Samba4 internal DNS, cache any records that were
looked up from a forwarder, and then secondly what is the default
timeout for waiting for a DNS lookup off of a DNS forwarder?

I've installed two new Samba4 PDC's(using the built in DNS server and
not named) for two separate sites, and both had an existing DNS server
using named configured with multiple forwarders and both sites
retained the existing named DNS servers and forwarders. Since the
Samba4 PDC's went in users now have their DNS's set to the Samba4
machines and nothing else. Then the Samba4 is configured to just
lookup any Internet names it doesn't know about via the single
forwarder off of the older caching named servers.

Sporadically I seem to get an instant DNS resolution failure(almost
like my named caching DNS server wasn't even checked), but if you
refresh or run the same ping again, the name then resolves straight
away. I can understand if a DNS name doesn't resolve straight away due
to line speed issues or packet loss, but usually I'd expect this would
take a few seconds to timeout and not fail instantly.

If I use my old named caching DNS server I don't get the same
behaviour, does anyone know why we would experience this?

Thank you.

Regards.

Neil Wilson.

On 11:55:13 wrote Neil:
> Hi guys,
> 
> I know this sounds vague and I'll try to explain in more depth now,
> but firstly, does Samba4 internal DNS, cache any records that were
> looked up from a forwarder, and then secondly what is the default
> timeout for waiting for a DNS lookup off of a DNS forwarder?
> 
> I've installed two new Samba4 PDC's(using the built in DNS server
and
> not named) for two separate sites, and both had an existing DNS
> server using named configured with multiple forwarders and both
> sites retained the existing named DNS servers and forwarders. Since
> the Samba4 PDC's went in users now have their DNS's set to the
> Samba4 machines and nothing else. Then the Samba4 is configured to
> just lookup any Internet names it doesn't know about via the single
> forwarder off of the older caching named servers.
> 
> Sporadically I seem to get an instant DNS resolution failure(almost
> like my named caching DNS server wasn't even checked), but if you
> refresh or run the same ping again, the name then resolves straight
> away. I can understand if a DNS name doesn't resolve straight away
> due to line speed issues or packet loss, but usually I'd expect this
> would take a few seconds to timeout and not fail instantly.
> 
> If I use my old named caching DNS server I don't get the same
> behaviour, does anyone know why we would experience this?
No,
but I have had a similiary situation some weeks ago. I solved the 
problem this way:

switch from internal DNS to bind8 or bind9 with DLZ, see samba wiki
declare this bind instance as "forward only"
make your current internal forwarders a slave for your samba DNS
> 
> Thank you.
> 
> Regards.
> 
> Neil Wilson.

-- 

Regards

	Harry Jede