Installing Zimbra inside network with no static IP

[Rtaxerxes]

Hi all,

Apologies if this is covered somewhere, I have been trolling the forums and googling, but I am getting a little confused on some of the terminology.

My current setup is:
I have a domain registered, lets say fiftynine.co.za and hosted by webhost. Since I am in South Africa, I only have 2GB of hosted space.
I have ADSL connection, no static IP, with a max upload speed of 512k. I have 10 users sharing this through an Ubuntu box acting as router, NAT and proxy.
I have an Exchange server set up that is basically allowing internal mail and that is syncing and backing up mail. Some users have desktops and laptops and the exchange server syncs their mail. This also provides some shared calendars and contacts using public folders.
My internal domain has been setup as fiftynine.local.

I would like to use Zimbra, partly because Exchange is a resource hog and expensive and doesn't talk nicely to the 5 Mac clients. Also Entourage is terrible. Sending internal mail required changing the mail account you used, and if you made a mistake, it would obviously not send out to the internet.

I am running a Zimbra VM on the linux server currently, and have set up accounts and shared calendars. I set that internal domain to fifty.nine. Now I need some help with mail. I tried to set up an external SMTP relay, but I am getting an error that my domain doesn't have an A or MX record.

Essentially I would like advice on how to set this up so that Zimbra would be available worldwide, and all mail functions available. I should be able to figure out passing Zimbra through Apache on the router, but as far as setting up my domain, I have no idea. I have read about split-dns, but I'm not sure what it achieves, two domains or 1 domain handled by different DNS servers...

Can I set up Zimbra to handle the domain fiftynine.co.za or must it be an arb domain because it is internal. I would still like to make use of my hosts mail servers for max reliability, becuase ADSL may be too slow and unreliable and power can be an issue in South Africa.

Please point me towards the best setup to achieve this.

Thanks in advance.

[phoenix]

Originally Posted by Rtaxerxes

Since I am in South Africa, I only have 2GB of hosted space.

Let's start with that statement. What do you mean by 2GB of hosted space? Do you mean disk space or RAM? If you mean disk space then you can't install ZImbra on that.

[Rtaxerxes]

It is disk space at our web host. I just mentioned that because if the users used our web host as an IMAP server, we'd run out of disk space very quickly.

[Rtaxerxes]

Can we start this by someone telling me if I can set my domain name inside the network (behind the router) to be the same as my external domain name? ie. fiftynine.co.za inside the network and out?

[phoenix]

You can set the domain name on your LAN to anything you like, for simplicity I usually recommend using the same domain name as your external domain - follow the details for Split DNS You will also need external DNS A & MX records for your domain.

[Rtaxerxes]

So if I set a split dns up, my external DNS would point to my webhosting company's servers. Could my clients then check their mail on the external server, download it to their machine, and then it would send it to the Zimbra server and it would keep a copy? Like a cached Exchange server?

[phoenix]

I'm not quite sure where the web hosting service fits into this scenario, do they just host your DNS records or are they receiving mail for your domain?

[Rtaxerxes]

They are currently hosting our mail and dns.

[phoenix]

If the mail is hosted externally the you have three choices of getting it into Zimbra and it depends on whether your host has a single mailbox for all your mail or individual mailboxes for each user. If they have a single mailbox then you could use fetchmail (search the forums for the words 'fetchmail aggregation') to get it into Zimbra and drop it into the mailboxes, if they have individual mailboxes for each user then there's a feature in Zimbra (in the users Preferences/Accounts tab) that will allow each user to get external mail and view it in their Zimbra account. The final option is to have the mail delivered directly to your Zimbra server, that's the most effective solution.

[dwmtractor]

I would add to Bill's suggestions a couple of points (maybe more like questions) based on your earlier comments:

1. You mentioned your concern with power being a problem. If I understand you correctly, you're saying that you want Zimbra to be your main server, but to have the ISP remain as a backup. Do you mean by this that the ISP would be an alternate place for your users to check their mail, or just that the ISP would function basically to cache your email till Zimbra could come back up and haul it all down? I ask because if your users check their email on the ISP, but fail to leave it there for later download, the Zimbra box will never see it. Additionally, if they reply on the ISP, Zimbra's outbox won't get it either.
2. If your Zimbra box has the same domain as your ISP-hosted email, you could run into a problem with other mail recipients who use Reverse-DNS lookup as a spam control. By this I mean that if your sent mail comes from the Zimbra box, and yet when my mail server's RDNS query returns your ISP (presumably a different IP address and maybe a different range), I'll reject the email. This may be rectified if your ISP can function as a "smarthost" and Zimbra sends all outgoing mail through that smarthost--but you'll have to get advice from others on that as I'm not familiar with the setup myself.

Originally Posted by Rtaxerxes

So if I set a split dns up, my external DNS would point to my webhosting company's servers. Could my clients then check their mail on the external server, download it to their machine, and then it would send it to the Zimbra server and it would keep a copy? Like a cached Exchange server?

No, you don't want to (I don't think you CAN) do it that way. Your external DNS could point to the webhosting servers, yes. But if your clients check their mail there AND DOWNLOAD IT there's no getting it back up to the Zimbra server. They need (through external accounts on Zimbra, or else with fetchmail) to download the mail TO THE ZIMBRA SERVER. As I said in #1 above, if they do a POP check to the ISP, they must be set up to "leave the message on the server" so that when Zimbra checks (presumably later) there's still a message left to download.

Having worked in Africa (tho not S.A.) myself I can sympathize with your power concerns. I'm wondering if a good UPS might not be your solution--just how intermittent is the power at your location? And for how long do you usually see it go down? A good hefty external battery connected to your UPS might just buy you enough time to keep the server up, as long as too many other things don't also get plugged into the UPS.