Zimbra proxy must be installed on the identified proxy nodes in order to set up HTTP proxy. For example, users can always use their web browser to visit the proxy server at The connection from users whose mailboxes live on mbs1.
Zimbra Proxy is installed with ZCS and is set up during Installation from the ZCS configuration menus.
POP1 was specified in RFC 918 (1984), POP2 by RFC 937 (1985). Its current specification is RFC 1939, updated with an extension mechanism, RFC 2449 and an authentication mechanism in RFC 1734.
The original POP3 specification supported only an unencrypted USER/PASS login mechanism or Berkeley .rhosts access control.
Learn about the different ways certain email protocols work and how each one works with your Comcast Business email.
An email protocol is an internet standard used for transmitting email and in some cases contacts and calendar items.
End users can connect using POP3, IMAP, POP3S (Secure POP3), or IMAPS (Secure IMAP).
For example, proxying allows users to enter imap.as their IMAP server.
If your actual configurations or settings differ from what is listed in any of the steps below, please contact Comcast Business Customer Support.
MAPI is a proprietary Microsoft protocol that allows the Microsoft Outlook email client to fully utilize all of the features of an Exchange server including email, shared address books, calendars and public folders.
Although most POP clients have an option to leave mail on server after download, e-mail clients using POP generally connect, retrieve all messages, store them on the user's PC as new messages, delete them from the server, and then disconnect.
Other protocols, notably IMAP, (Internet Message Access Protocol) provide more complete and complex remote access to typical mailbox operations.