Multiple Domains One Server One IP

[johandl]

We are new to Zimbra and email hosting in general, though we have a good understanding of the OS and the general terms defining the technology. In our current corporate environment we are trying to build a ZCS5.011 server to manage several existing email domains locally. These domains all reside with our current ISP, including name servers, MX and A records.

Our ZCS server has one public IP number sourced from our NEW ISP, run through SmoothWall, and through a horizon DNS setup a single internal IP number that we assigned. Zimbra Proxy Server (IMAP/POP Proxy) has not been installed. All the existing email domains reside with the current and soon to be OLD ISP.

We have started our testing of the ZCS server by setting up one domain - mail.domain.co.za - asked of us when the server is installed, and two ZCS domains that include virtual hosts as well, mail.domain2.co.za and mail.domain3.com. Only the latter two domains have their A and MX records amended now to point to our ZCS Server public IP number. The first or former domain name has not yet been moved, as it too is originally hosted by the soon-to-be-old ISP, but we are not testing that domain as yet, and therefore we only use it to authenticate web users of the ZCS Server.

When we test this setup we find the following results happen:
1. Timeouts on public email domains used to send emails to from the two test ZCS domains.
2. Intermittant POP reception to these two test ZCS domains.

What we are wanting is some assistance in a diagram of sorts that better explains the correct flow of traffic between MX, A, and name servers, and the local ZCS server, and that someone can help explain to us in terms of our scenario as explained above?
Also, it would be good to understand, having people access this ZCS server using Thunderbird and Outlook, whether we should be running Proxy as well?

Please let us know of posting copies if certain log entries would help.

[uxbod]

Welcome to the forums

Originally Posted by johandl

1. Timeouts on public email domains used to send emails to from the two test ZCS domains.
2. Intermittant POP reception to these two test ZCS domains.

Would you expand on the above two errors please as I am not sure what you mean ? Outbound emails are delayed ? Have you checked /var/log/zimbra.log for any error messages ?

[johandl]

At closer inspection we see that the timeouts we experience are usually where our outgoing email headers include the localhost IP (127.0.0.1), which we believe is wrong and may be the cause of those emails never reaching their destination.
We are also concerned that the domain name we chose for the default domain of the ZCS server reflects a public domain also being used for emails. We realize now that emails to and from those @domain.co.za addresses internally sent by our staff may be intercepted by the ZCS Server and either passed back to what it believes the correct inbox is, or bounced to the internal queues when the ZCS Server does not have such an email@domain.co.za address listed within itself.

As requested here is the last similar log entry showing a failure (apologies for the edited domain names):
Errors
2009-02-24 16:20:23 bounced (domain.co.za)
2009-02-24 16:22:05 deferred (Host or domain name not found. Name service error for name=domain4.com type=MX: Host not found, try again)
2009-02-24 15:03:53 bounced (host xxx.CURRENT_ISP.co.za[41.xxx.xxx.xx] said: 550 5.1.1 < johan@domain4.com>: Recipient address rejected: User unknown in relay recipient table (in reply to RCPT TO command))
2009-02-24 15:08:45 bounced (host xxx.CURRENT_ISP.co.za[41.xxx.xxx.xx] said: 550 5.1.1 < johan@domain4.com>: Recipient address rejected: User unknown in relay recipient table (in reply to RCPT TO command))
2009-02-24 13:11:36 deferred (host mx.wmint.net[196.25.210.122] said: 451 4.7.1 GreyShark: Grey listed for 01:58, please try again later. (in reply to RCPT TO command))
2009-02-24 15:24:01 bounced (domain.co.za)
2009-02-24 16:23:21 bounced (domain.co.za)


Sending emails to gmail.com for example does not fail and works consistantly.

(Ps. forum sessions time out pretty quickly )

[uxbod]

As you are on a private LAN you will need to ensure that a internal MX record exists for each of the domains you are hosting on your ZCS server; otherwise if it gets the public one it will traverse your internal network to the outside world.

[johandl]

Thanks for the quick replies, uxbod. I posted a reply just prior to your last one and then edited it to have a better log entry explaining our errors and now see that it disappeared. Not sure how, but anyway let me respond to your last reply: Do you mean that we should have MX records for the internal zone, the zone on the private LAN side of the split DNS? We have one entry at the moment, but only for the domain.co.za domain that is the ZCS server.

[uxbod]

Indeed. As you are on a private LAN your DNS should have a MX record for each domain you are hosting on your ZCS server. I have a couple of domains on my server and I run a split DNS with internal and external views. I ensure that any domain I host has a *valid* internal MX record which points to the private IP of my ZCS server.

[johandl]

Originally Posted by uxbod

Indeed. As you are on a private LAN your DNS should have a MX record for each domain you are hosting on your ZCS server. I have a couple of domains on my server and I run a split DNS with internal and external views. I ensure that any domain I host has a *valid* internal MX record which points to the private IP of my ZCS server.

Brilliant. That is very clear and makes absolute sense now. I will have the team implement and report back on Monday about our success or not. Have a good weekend!

[ec120]

Originally Posted by uxbod

Indeed. As you are on a private LAN your DNS should have a MX record for each domain you are hosting on your ZCS server. I have a couple of domains on my server and I run a split DNS with internal and external views. I ensure that any domain I host has a *valid* internal MX record which points to the private IP of my ZCS server.

Hi uxbod,

As I am totally new to this field (mail hosting) and I am trying to setup ZCS for 6 to 10 domains, I would like to ask you a question on your comment above;

I am running a Split DNS environment, and currently my one domain (the initial one I set ZCS up with) is working very well. With the rest of the domains would I need to add these in the same way to 1) "/etc/named.conf" 2) db file under "/var/named/db.x.x.com" 3) in "/etc/resolv.conf" and lastly in the "/etc/hosts" files?

THANK YOU in advance!

ec120

[phoenix]

Originally Posted by ec120

I am running a Split DNS environment, and currently my one domain (the initial one I set ZCS up with) is working very well. With the rest of the domains would I need to add these in the same way to 1) "/etc/named.conf" 2) db file under "/var/named/db.x.x.com" 3) in "/etc/resolv.conf" and lastly in the "/etc/hosts" files?

No, you don't need to do that.

[ec120]

Thank you for your quick reply phoenix, how would I add these additional domains?