Getting Zimbra Email Using IMAP/POP3
You can read your email on the iPhone just like you would with a desktop email client by setting it up for IMAP or POP3 access. IPhone users should only use the IMAP position. This option is available to both free Open Source users and paying Network Edition users.
Note: This method only syncs email messages. To access your Zimbra contacts and calendars, use either Zimbra Mobile Web client in the Safari browser or upgrade to Zimbra Network Edition.
SET UP:
Under Mail settings, select "Add Account..."
Select "Other"
Select "POP3 or IMAP"
Fill in the "Name", "Address", and "Description" fields
Provide "Host Name"( sunfire2.netcetra.com ), "User Name" ( yourname@yourdomain.com ), and "Password" in the "Incoming Mail Server" section. If your server requires a non-default TCP port specification, (110) use the hostname:port format in the "Host Name" field. (So like sunfire2.netcetra.com:110 ) SSL settings can be adjusted later under the "Advanced" section in the mail account settings.
In the "Outgoing Mail Server (SMTP)" section, provide settings for "Host Name"( sunfire2.netcetra.com ), "User Name" ( yourname@yourdomain.com ) and "Password" whatever it is I am not sure ). As with the incoming mail server, the "Host Name" setting accepts the hostname:port ( sunfire2.netcetra.com:25 or sunfire2.netcetra.com:587 ) format if the outgoing mail server uses a non-default TCP port. Save the configuration.
This for the NetCetra clients that are on the Zimbra servers. If you are squrrel mail please contact support.