samba - Feb 2019 - Samba AD Internal DNS, Postfix & Email Relay

Is there an extra step which must be taken to get postfix
to deliver email via a relay host when the postfix machine
is pointing to an samba internal DNS?

I did a test setup using a public DNS server and it worked.
Same setup where the machine (Debian 9) is pointing to a
samba DNS doesn't work.  The errors in the postfix log
seem to be DNS related.

Thanks,

Am 24.02.19 um 23:59 schrieb Marco Shmerykowsky via
samba:
> Is there an extra step which must be taken to get postfix
> to deliver email via a relay host when the postfix machine
> is pointing to an samba internal DNS?
> 
> I did a test setup using a public DNS server and it worked.
> Same setup where the machine (Debian 9) is pointing to a
> samba DNS doesn't work.  The errors in the postfix log
> seem to be DNS related.
besides that you should post said errors:

relayhost = [x.x.x.x]:25
relayhost = [hostname]:25

Hai Marco, 

For you own domains, dont point postfix to your internal DNS only, 
if done wrong you might miss dns info on the wan side and thats mostlikely your
error .

Setup a caching DNS and setup a forward zone to internal.domain.tld and
domain.tld. ( internet dns )
That makes sure that you dont break DKIM/DMARC/SPF/TLSA on the internet side. 


Greetz, 

Louis

> -----Oorspronkelijk bericht-----
> Van: samba [mailto:samba-bounces at lists.samba.org] Namens 
> Marco Shmerykowsky via samba
> Verzonden: zondag 24 februari 2019 23:59
> Aan: samba at lists.samba.org
> Onderwerp: [Samba] Samba AD Internal DNS, Postfix & Email Relay
> 
> 
> Is there an extra step which must be taken to get postfix
> to deliver email via a relay host when the postfix machine
> is pointing to an samba internal DNS?
> 
> I did a test setup using a public DNS server and it worked.
> Same setup where the machine (Debian 9) is pointing to a
> samba DNS doesn't work.  The errors in the postfix log
> seem to be DNS related.
> 
> Thanks,
> 
> -- 
> To unsubscribe from this list go to the following URL and read the
> instructions:  https://lists.samba.org/mailman/options/samba
> 
>

Talking for postfix, might be handy to know also. 

Ive setup MX record on the mailrelay.internal.domain.tld for the mail relay
server.
And ofcource the internet MX records.. 

For the internal member servers, the postfix setups are default, they lookup the
MX record for internal.domain.tld.
And if i must define a relay its smtp.internal.domain.tld, where smtp is a CNAME
to the relay servername internaly.
When i change my relay, i change the CNAME and MX record and im done for all my
other servers.

And no relay= , is defined in postfix's master.cf on other servers, except
if something is really needing it.

The relay contains and used transport maps 
#/etc/postfix/transport_maps.map
# the internal mail end point. 
domain.tld        smtp:mail.internal.domain.tld:25

The relay is named. 
mailrelay.domain.tld ( inet side)	(MX 10)
mailrelay.internal.domain.tld (lan side)	(MX 10) 

Combine this with the bind setup and your resolving is always correct. 

Greetz. 

Louis
> -----Oorspronkelijk bericht-----
> Van: samba [mailto:samba-bounces at lists.samba.org] Namens 
> Reindl Harald via samba
> Verzonden: maandag 25 februari 2019 0:16
> Aan: Marco Shmerykowsky; samba at lists.samba.org
> Onderwerp: Re: [Samba] Samba AD Internal DNS, Postfix & Email Relay
> 
> 
> 
> Am 24.02.19 um 23:59 schrieb Marco Shmerykowsky via samba:
> > Is there an extra step which must be taken to get postfix
> > to deliver email via a relay host when the postfix machine
> > is pointing to an samba internal DNS?
> > 
> > I did a test setup using a public DNS server and it worked.
> > Same setup where the machine (Debian 9) is pointing to a
> > samba DNS doesn't work.  The errors in the postfix log
> > seem to be DNS related.
> 
> besides that you should post said errors:
> 
> relayhost = [x.x.x.x]:25
> relayhost = [hostname]:25
> 
> 
> 
> -- 
> To unsubscribe from this list go to the following URL and read the
> instructions:  https://lists.samba.org/mailman/options/samba
> 
>

On 2/25/2019 3:36 AM, L.P.H. van Belle via samba wrote:
> Hai Marco,
> 
> For you own domains, dont point postfix to your internal DNS only,
> if done wrong you might miss dns info on the wan side and thats mostlikely
your error .
Likely.  Here is the error (ignore the ip's - messed them
up for this response):

Feb 25 16:22:10 sce252 postfix/smtp[3114]: 0D1E86E3A6D:
to=<marco at sce-engineers.com>, orig_to=<root>,
relay=mail.panix.com[1
6.8.1.8]:587, delay=317791, delays=317743/0.02/48/0.1, dsn=4.1.8,
status=deferred (host mail.xxxx.com[6.4.1.9] said:
  450 4.1.8 <root at sce252.internal.company.com>: Sender address
rejected: Domain not found (in reply to RCPT TO comm
and))
> 
> Setup a caching DNS and setup a forward zone to internal.domain.tld and
domain.tld. ( internet dns )
> That makes sure that you dont break DKIM/DMARC/SPF/TLSA on the internet
side.
UGH..... Another thing to learn :(
> 
> 
> Greetz,
> 
> Louis
> 
> 
>> -----Oorspronkelijk bericht-----
>> Van: samba [mailto:samba-bounces at lists.samba.org] Namens
>> Marco Shmerykowsky via samba
>> Verzonden: zondag 24 februari 2019 23:59
>> Aan: samba at lists.samba.org
>> Onderwerp: [Samba] Samba AD Internal DNS, Postfix & Email Relay
>>
>>
>> Is there an extra step which must be taken to get postfix
>> to deliver email via a relay host when the postfix machine
>> is pointing to an samba internal DNS?
>>
>> I did a test setup using a public DNS server and it worked.
>> Same setup where the machine (Debian 9) is pointing to a
>> samba DNS doesn't work.  The errors in the postfix log
>> seem to be DNS related.
>>
>> Thanks,
>>
>> -- 
>> To unsubscribe from this list go to the following URL and read the
>> instructions:  https://lists.samba.org/mailman/options/samba
>>
>>
> 
>