Shared-Domain Migration Strategy

[straccio]

Hi to all,
i'm testing a migration to Zimbra (for now, the open source one) from a legacy imap/pop3/smtp server.

After a lot of reading i agree to try the shared domain migration strategy with pop3/imap proxying to the old mail server because i need to migrate one user at time in a transparent mode.

To do this i suppose to place Zimbra (maybe only the proxy) in front of the current (old) mail server and fetch al pop/imap/smtp requests.

For the smtp i have made

zmprov md mydomain.com zimbraMailCatchAllAddress @mydomain.com
zmprov md mydomain.com zimbraMailCatchAllForwardingAddress @mydomain.com
zmprov md mydomain.com zimbraMailTransport smtp:oldserver

And all works fine, all emails not hosted in zimbra are forwarded to the old server.

Now i need to configure the pop/imap access but i don't know how to provide this settings.
I can only suppose who i need to create all accounts and set the MailTransport per account for the smtp relay, but after a lot of searchs with google, your forum and wiki i can't find how to set and unset the imap/pop proxy.

Best regards and good job.
PS: sorry for my bad English.

[straccio]

Up, no help for this?

[phoenix]

Originally Posted by straccio

Now i need to configure the pop/imap access but i don't know how to provide this settings.
I can only suppose who i need to create all accounts and set the MailTransport per account for the smtp relay, but after a lot of searchs with google, your forum and wiki i can't find how to set and unset the imap/pop proxy.

I don't really understand your question. There is no need for any Zimbra proxy in this scenario. You point a users to the server (vai DNS) and they use the relevant POP3 or IMAP port to access their email. If their mail is still on the old server then they access that as normal.

[straccio]

I can't change the DNS and the server setting on the client.
Example:
unique mx record domain.com who point to Zimbra
a@domain.com is in Zimbra migrated
b@domain.com is in OldServer not yet migrated

When b@domain.com open a pop/imap session to domain.com (Zimbra server) the session need to be forwarded to the old server, or something like this.

I need to migrate one user at time, without do any change to the clients, completely transparent for all users.

really tnx

[straccio]

You don't understand?

[phoenix]

Originally Posted by straccio

You don't understand?

Yes, I understand perfectly what you've said - why not follow the Split Domain wiki article?

[LMStone]

Originally Posted by straccio

You don't understand?

Let me try a different take on this...

The shared-domain migration strategy as I understand it means you have MX records for both the new Zimbra system and the legacy mail system, and both systems are in use until all users' mailboxes are migrated from the old system.

Zimbra is typically configured to believe that all mailboxes that exist on a domain Zimbra hosts are the only mailboxes that exist for that domain. So if you have bob@example.net and shirley@example.net on the old server, and only bob@example.net on the Zimbra server, until you get Shirley's email migrated over to Zimbra, you want the Zimbra server to send any email it receives for Shirley to the legacy system. Normally, Zimbra will just reject email it receives for Shirley. Nor will Bob be able to send Shirley an email from Zimbra until her mailbox is created in Zimbra.

In fact, GMail works out of the box with a shared domain configuration and why it is easy and less disruptive to end users to migrate to GMail.

Say you have 2,000 mailboxes on your Exchange system on domain acme.com. In GMail you create the acme.com domain and add MX records for the assigned GMail servers so that public DNS has MX records now for both GMail and your Exchange server (or the Smart Host in front of Exchange).

In GMail, you then create the first user, say, john.doe@acme.com and use the tools to copy John's existing email etc. from Exchange into GMail. You then tell John he is ready to use GMail. When John logs in to GMail, even though his is the only mailbox in GMail on that domain, when John goes to send an email to Jane.Seymour@acme.com, GMail, instead of rejecting the email as Zimbra would, does an MX lookup and sends the email to Jane via the old Exchange server.

With this configuration, it's easy to migrate a few, or many, users from the old system to GMail over a few days, weeks or months, with no negative impact on the users and only a change to the users' email client.

Zimbra has a Shared Domain migration document from 2006 which talks about migrating mailboxes 100K at a time. Sounds like you've read that document since the use of proxy figures in the migration strategy documented there.

If my understanding of what you want to accomplish is correct, I would look instead to utilize Postfix's Transport tables within Zimbra, which you'll need to populate with all of the email addresses in the domain, using a different transport if the mailbox is on the legacy system or in ZImbra. See Postfix manual - transport(5).

As you migrate mailboxes, update the Postfix transport table used by Zimbra and reload Postfix.

Once the migration is completed, you can then revert Zimbra's Postfix configuration back to the original.

If my understanding of what you want to accomplish is not correct, I apologize and would ask that you try once more to clarify for us!

Hope that helps,
Mark