samba - Feb 2022 - Member join, dns issues

On Thu, 2022-02-24 at 09:04 -0800, Greg Sloop <gregs at sloop.net>
wrote:
> 1) We've used local for many years, and rooting it out is kind of a
> huge pain. 
> So, what happens if AVAHI is still on and we're using local? (Is
> there some specific failure, or potential DNS confusion? I'd assume
> that FQDN references work fine, but short names might be ambiguous.)
> In any case, while I know .local isn't "recommended"
what's the
> actual failure point?
The problem is that you will have two services replying to a potential
dns request, if, as you say' the request is for a short hostname, the
wrong service may reply. Having said that, if your client is a domain
member, you shouldn't need Avahi because dns should be providing the
hosts info.
The problem was compounded by Microsoft advising that '.local' was
perfectly acceptable, they have now stopped doing this and actively
recommend you don't use it.
> 
> 2) >This generally occurs if your client does not resolve to a FQDN
> before
> the join.
> 
> Explain that more fully, please.
I can only speak from experience, but when the client dns is setup
correctly it works for myself. If 'hostname -d' doesn't return the
dns
domain, then I get the error you did.
> The AD servers we're joining certainly don't know about this
server.
Perhaps not, but they should be in the same dns domain.
> It's IP is static.
> But the (future) member server does know how to resolve the AD domain
> DNS entries, and it has a def in the hosts file for itself.
> So, what you mean by "your client does not resolve to a FQDN before
> the join" is not clear.
If that is the case, then I will have to think about this. With the
correct line in /etc/hosts and 'hostname -*' producing the correct
output, the join has always worked for myself.

Rowland

So, yes, hostname -d does produce the 3rd level domain we're using for the
domain.
ad.somedomain.local - in our case.

cat /etc/hosts
---
127.0.0.1 localhost
10.1.2.4 fileserver.ad.somedomain.local fileserver
---

So, something sure seems broken.
This is on Ubuntu 20.04, using the latest packages from Louis.



On Thu, Feb 24, 2022 at 9:36 AM Rowland Penny via samba <
samba at lists.samba.org> wrote:
> On Thu, 2022-02-24 at 09:04 -0800, Greg Sloop <gregs at sloop.net>
wrote:
> > 1) We've used local for many years, and rooting it out is kind of
a
> > huge pain.
> > So, what happens if AVAHI is still on and we're using local? (Is
> > there some specific failure, or potential DNS confusion? I'd
assume
> > that FQDN references work fine, but short names might be ambiguous.)
> > In any case, while I know .local isn't "recommended"
what's the
> > actual failure point?
>
> The problem is that you will have two services replying to a potential
> dns request, if, as you say' the request is for a short hostname, the
> wrong service may reply. Having said that, if your client is a domain
> member, you shouldn't need Avahi because dns should be providing the
> hosts info.
> The problem was compounded by Microsoft advising that '.local' was
> perfectly acceptable, they have now stopped doing this and actively
> recommend you don't use it.
>
> >
> > 2) >This generally occurs if your client does not resolve to a FQDN
> > before
> > the join.
> >
> > Explain that more fully, please.
>
> I can only speak from experience, but when the client dns is setup
> correctly it works for myself. If 'hostname -d' doesn't return
the dns
> domain, then I get the error you did.
>
> > The AD servers we're joining certainly don't know about this
server.
>
> Perhaps not, but they should be in the same dns domain.
>
> > It's IP is static.
>
> > But the (future) member server does know how to resolve the AD domain
> > DNS entries, and it has a def in the hosts file for itself.
> > So, what you mean by "your client does not resolve to a FQDN
before
> > the join" is not clear.
>
> If that is the case, then I will have to think about this. With the
> correct line in /etc/hosts and 'hostname -*' producing the correct
> output, the join has always worked for myself.
>
> Rowland
>
>
>
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