[plug] cannot send mail to certain domains

Wed Feb 3 14:13:47 WST 2010

Jon L Miller wrote:
> Hi Peter,
> Yes, I have an in-house mail server with a private IP. 
> Yes I also had 2 NS servers that had public IP and they are now turned off.
> So I moved my clients and my DNS information off-site to MelbourneIT (MIT).
> The mail server was configured to use the local DNS servers, once they (NS)
> were turned off; the mail server was configured to use the off-site NS
> (MIT).
> >From the server I can ping both the local IP and the external IP (Cisco
> router external interface). The Cisco is set to NAT inside traffic to the
> external IP and all traffic that is bound for the external IP is NAT back to
> the inside server(s) soon to be 1.
>
> All the DNS information A and MX pointer are handled by MIT; Amnet handles
> the rDNS information.  
> The internal servers are configured (resolv.conf) to look to Telstra and
> Amnet.  Reason, when a friend of mine and myself did a comparison we found
> that the MIT servers resolves hotmail.com as something completely different
> than what Telstra and Amnet did.  Therefore I decided to use Telstra as the
> primary and Amnet as a secondary NS.
>
> Currently the only incoming mail is from plug... gotta like it.
>
> Jon
>
>
>
>   
OK, so I have the correct 'picture' in my head.

If you do a ping from the mail server:   'ping mmtnetworks.com.au', what 
IP address do you get in reply?

A ping from the local server should return it's internal 192.....  
address and NOT the external 203.... address

Is this the case?

.... just read your last e-mail...

Your hosts file should also contain  'mmtnetworks.com.au' and/or 
'mail.mmtnetworks.com.au'  (not just mntlnx.....)

Your MX record: 

;; QUESTION SECTION:
;mmtnetworks.com.au.        IN    MX

;; ANSWER SECTION:
mmtnetworks.com.au.    86400    IN    MX    10 mail.mmtnetworks.com.au.

....

So mail (from the Internet) is being sent to mail.mmtnetworks.com.au and 
not mntlnx.mmtnetworks.com.au  (the name you have in your hosts file)......

If you ping 'mail.mmtnetworks.com.au from the server, what do you get?

P.

>
> -----Original Message-----
> From: plug-bounces at plug.org.au [mailto:plug-bounces at plug.org.au] On Behalf
> Of Peter
> Sent: Wednesday, 3 February 2010 1:25 PM
> To: plug at plug.org.au
> Subject: Re: [plug] cannot send mail to certain domains
>
> Jon Miller wrote:
>   
>> Hi Matt,
>> Yes I understand they are two separate issue, unfortunately this 
>> server has several issues, so I'm asking questions not in any 
>> particular order.  I'll change that so that we can be on the same page 
>> at the same time.
>>
>> ok first thing first
>> There is mention of the internal ip address in the /etc/postfix/transport.
>> Is there supposed to be anything in there?
>>
>> Jon
>>
>>
>>
>>     
>>> Date: Wed, 3 Feb 2010 12:34:15 +0800
>>> From: zombie at penguincare.com.au
>>> To: plug at plug.org.au
>>> Subject: RE: [plug] cannot send mail to certain domains
>>>
>>> Hi Jon
>>>
>>> You seem to be confusing the two seperate issues here.
>>>
>>> The "cannot send mail to certain domains" is a DNS issue. The "I can 
>>>       
>> not
>>     
>>> receive email" is a local postfix configuration issue.
>>>
>>> On Wed, 3 Feb 2010, quoth Jon Miller:
>>>
>>>       
>>>> Feb 3 12:22:07 mmtlnx postfix/smtp[25064]: 4B24D365E2:
>>>> to=<jlmiller at mmtnetworks.com.au>, relay=none, delay=2, status=bounced
>>>> (mail for 192.168.2.247 loops back to myself)
>>>>         
>>> Where did the 192.168.2.247 come from?
>>>
>>> Is that anywhere in your postfix/main.cf or /etc/aliases or 
>>>       
>> /etc/postfix/virtual?
>>     
>>>> What I do not understand is why it's still looping back to the server.
>>>>         
>>> Because the server doesn't realise the message is for itself, so it 
>>>       
>> tries
>>     
>>> to pass it on, only to discover it is talking to itself.
>>>
>>> - Matt
>>> _______________________________________________
>>> PLUG discussion list: plug at plug.org.au
>>> http://www.plug.org.au/mailman/listinfo/plug
>>> Committee e-mail: committee at plug.linux.org.au
>>>       
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> PLUG discussion list: plug at plug.org.au
>> http://www.plug.org.au/mailman/listinfo/plug
>> Committee e-mail: committee at plug.linux.org.au
>>   
>>     
> Hi Jon,
>
> Can I ask for a bit of general clarification (I've only been skimming 
> you e-mails)? 
>
> If I understand you correctly, you have an in-house mail server (private 
> IP) and you had a DNS (in house?) but moved this off site to MelbourneIT 
> hosted DNS servers.....    Is that right?
>
> If your mail server was configured to use a local DNS but is now looking 
> to the web (external DNS) it will get confused. 
>
> Eg.  If you ping mmtnetworks.com.au from the server, does it reply 
> 192.168.2.247 or 203.153.225.77 ?    If the server itself thinks that 
> mmtnetworks.com.au is out on the the internet (203.153.225.77), local 
> delivery won't work:  You cannot send and receive mail through the same 
> physical connection.
>
> If you do not have an in-house DNS, you need to make sure any local 
> domains are (at the very least) in the 'hosts' file on the local server 
> and /or in your DHCP config for other machines on your network.
>
> Or did I completely misunderstand what you are trying to do?
>
> Cheers,
> Peter
> _______________________________________________
> PLUG discussion list: plug at plug.org.au
> http://www.plug.org.au/mailman/listinfo/plug
> Committee e-mail: committee at plug.linux.org.au
>
> _______________________________________________
> PLUG discussion list: plug at plug.org.au
> http://www.plug.org.au/mailman/listinfo/plug
> Committee e-mail: committee at plug.linux.org.au
>
>
>   