ZCS Administrator Guide 8.0

Network Edition

Global Configuration

Global Settings apply to all accounts in the Zimbra servers. They are initially set during installation. You can modify the settings from the administration console.

Configurations set in Global Settings define inherited default values for the following objects: server, account, COS, and domain. If these attributes are set in the server, the server settings override the global settings.

To configure global settings, go to the administration console Configure > Global Settings page.

Configured global settings include:

Default domain

Maximum number of results returned for GAL searches. The default is 100.

Setting how users view email attachments and what type of attachments are not allowed

Configuring authentication process, setting the Relay MTA for external delivery, enabling DNS lookup and protocol checks

Set the spam check controls and anti-virus options for messages received that may have a virus

Set up free/busy scheduling across a mix of ZCS servers and third party email servers

Customize themes color scheme and add your logo to the themes

Configure the company name that displays when external guests log on to see a shared Briefcase folder

Configure Backup default directory and backup notification information

Set the global HSM schedule for when messages should be moved to a secondary storage space

View the current Zimbra license information, update the license if necessary and view the number of accounts created

General Global Settings

The General Information page includes the following settings.

 

Option	Description
Most results returned by GAL search	The maximum number of GAL results returned from a user search. The default is 100.
Default domain	Domain that users’ logins are authenticated against.
Number of scheduled tasks that can run simultaneously	Number of threads used to fetch content from remote data sources. The default is 20. If set too low, users do not get their mail from external sources pulled down often enough. If set too high, the server may be consumed with downloading this mail and not servicing “main” user requests.
Sleep time between subsequent mailbox purges	The duration of time that the server should “rest” between purging mailboxes. By default, message purge is scheduled to run every 1 minute. See the Customizing Accounts chapter, section Setting Email Retention Policy on page 149. Note: If the message purge schedule is set to 0, messages are not purged, even if the mail, trash and spam message life time is set.
Maximum size of an uploaded file for Briefcase files (kb)	The maximum size of a file that can be uploaded into Briefcase. Note: the maximum message size for an email message and attachments that can be sent is configured in the Global Settings MTA page
Admin help URL and Delegated admin help URL	If you do not want to use the ZCS Help, you can designate the URL that is linked from the administration console Help

Setting Up Email Attachment Rules

Global email attachment settings allow you to specify global rules for handling attachments to an email message. You can also set rules by COS and for individual accounts. When attachment settings are configured in Global Settings, the global rule takes precedence over COS and Account settings.

The following attachment setting options can be configured from the Global Settings Advanced page. To set by COS or account, go to their Advanced page, Attachment Settings section.

 

Option	Description
Attachments cannot be viewed regardless of COS	Users cannot view any attachments. This global setting can be set to prevent a virus outbreak from attachments, as no mail attachments can be opened.
Attachments are viewed in HTML regardless of COS	Email attachments can only be viewed in HTML. The COS may have another setting but this global setting overrides the COS setting.
Attachments are viewed according to COS	This global setting states the COS sets the rules for how email attachments are viewed

Blocking Email Attachments by File Type

You can also reject messages with certain types of files attached. You select which file types are unauthorized from the Common extensions list. You can also add other extension types to the list. Messages with those type of files attached are rejected. By default the recipient and the sender are notified that the message was blocked. If you do not want to send a notification to the recipient when messages are blocked, you can disable this option from the Global Settings>Attachments page.

Global MTA Settings

The Global Settings>MTA page is used to enable or disable authentication and configure a relay hostname, the maximum message size, enable DNS lookup, protocol checks, and DNS checks.

 

Authentication	Authentication should be enabled, to support mobile SMTP authentication users so that their email client can talk to the Zimbra MTA. TLS authentication only forces all SMTP auth to use Transaction Level Security to avoid passing passwords in the clear.
Network	Web mail MTA Host name and Web mail MTA Port. The MTA that the web server connects to for sending mail. The default port number is 25. The Relay MTA for external delivery is the relay host name. This is the Zimbra MTA to which Postfix relays non-local email. If your MX records point to a spam-relay or any other external non-Zimbra server, enter the name of that server in the Inbound SMTP host name field. This check compares the domain MX setting against the zimbraInboundSmtpHostname setting, if set. If this attribute is not set, the domain MX setting is checked against zimbraSmtpHostname. MTA Trusted Networks. Configure trusted networks that are allowed to relay mail. Specify a list of network addresses, separated by commas and/or a space. If Enable DNS lookups is checked, the Zimbra MTA makes an explicit DNS query for the MX record of the recipient domain. If this option is disabled, set a relay host in the Relay MTA for external delivery. If Allow domain administrators to check MX records from Admin Console is checked, domain administrators can check the MX records for their domain.
Milter Server	If Enable Milter Server is checked, the milter enforces the rules that are set up for who can send email to a distribution list.
Archiving Configuration	If you installed the Archiving feature, you can enable it here.
Messages	Set the Maximum messages size for a message and it’s attachments that can be sent. Note: To set the maximum size of an uploaded file to Briefcase, go to the General Information page. You can enable the X-Originating-IP header to messages checkbox. The X-Originating-IP header information specifies the original sending IP of the email message the server is forwarding.
Policy Service Checks	Customize zimbraMtaRestriction (restrictions to reject some suspect SMTP clients).
Protocol checks	To reject unsolicited commercial email (UCE), for spam control.
DNS checks	To reject mail if the client’s IP address is unknown, the hostname in the greeting is unknown, or if the sender’s domain is unknown. Add other email recipient restrictions to the List of RBLs field. Note: RBL (Real time black-hole lists) can be turned on or off from the Zimbra CLI. See the section Adding RBLs using the CLI on page 47.

Global IMAP and POP Settings

IMAP and POP access can be enabled as a global setting on the Global Settings>IMAP or POP pages or by editing a server’s IMAP or POP pages.

When you make changes to the IMAP or POP settings, you must restart ZCS before the changes take effect.

IMAP and POP3 polling intervals can be set from the administration console COS Advanced page. The default is to not set the polling interval.

Note:

If IMAP/POP proxy is set up, making sure that the port numbers are configured correctly.

With POP3, users can retrieve their mail stored on the Zimbra server and download new mail to their computer. The user’s POP configuration in their Preference>Mail page determines how their messages are downloaded and saved.