Non SSL POP3 connections to Zimbra being rejected - fixed
The problem whereby client devices trying to connect to zimbra using non SSL POP3 connections has been fixed as of 10:25 GMT this morning. The issue affected only a small number of mailboxes.
Details
We are migrating to a new 64bit Zimbra platform to allow for future expansion and to keep in line with Zimbra's latest best practice guidelines. This migration involves moving mailboxes off of their 32bit host servers onto new 64bit replacements. So far, all but one of the mailbox servers have been fully and successfully migrated and we are 50% through the final server's mailboxes (many of these 50% were migrated over this last weekend). This final server, although configured to allow non SSL connections for POP3 had an unrelated LDAP attribute set in a way which meant that non SSL connections were effectively blocked. We have reversed this setting, restarted the services and can now confirm that as of 10:25 GMT this morning, clear text POP3 connections are being accepted without issue. Our apologies for any inconvenience this may have caused.
Summary of Protocols requiring SSL
POP3 - not required, but recommended
IMAP - SSL must be enabled
HTTP - Optional (may change in future - see below)
ActiveSync - Optional (may change in future - see below)
Future SSL related changes
We are planning to set our Zimbra platform to force SSL for HTTP and ActiveSync but further testing is required to ensure complete client compatibility and to assess the impact before we go ahead. We will issue a notification well in advance of any change to allow you time to inform your users.
