On Saturday 25th April 2009 at 9am we will update the A host record of the primary unbranded Zimbra domain so that all incoming connections terminate at our Zimbra Proxy Cluster. The impact on end users should be zero, however, it is recommended that resellers read the details below to fully understand the background to this change.

Any resellers using their own URL, especially if they have created CNAME or Host records resolving to 217.154.106.217 should take note of the details below.

Details

[zimbra . protectedservice . net] will be changed to resolve to 217.154.106.232

Background Information

Currently, when users access their Zimbra mailbox, all connections are handled by Zimbra Proxy - a new fairly new feature of Zimbra which is able to route users to the actual server which hosts their mailbox. Any Zimbra mailbox server can provide proxy server duties and we have been using the Proxy feature on our production Zimbra platform in this way for nearly a month with great success. The change outlined above means that our primary domain will now resolve to our dedicated Zimbra Proxy cluster running on multiple servers configured for High Availability. This has also been in production for some weeks and we have performed various test migrations similar to what we will do on Saturday without any noticeable effect on users.

Proxied Protocols

Zimbra Proxy handles all Zimbra protocols except for XMPP (Jabber), therefore users who wish to make use of an external IM client (Adium/Pidgin etc) should work out the hostname of the server their mailbox is hosted on and use it as the server name in their IM client. It is possible to work out which server hosts a mailbox by viewing the email headers of a received email in the mailbox concerned (look for the received: header field - it will contain a server name similar to zimbra-mbox[X]....)