Advanced Administration Tasks#

In this section we describe and outline a few advanced tasks, providing quick directions to carry them out.

Role-based Access Control#

Carbonio uses a delegation mechanism to allow the principal administrator to assign roles and permission to other users with the purpose of sharing with them the administration tasks and duties, electing them as either Global or Delegated Administrator, who have different privileges to configure and manage these features.

In the context of the management of Anti-Virus and Anti-Spam functionalities, each Administrator, either Global or Delegated, can access with the personal account and be able to control and manage them, according to permissions granted.

Server-side Management of E-mails#

Carbonio's MTA (Postfix) receives e-mail by means of the SMTP protocol and forwards it to the correct e-mail queue according to the user’s username (this coincides with the user’s e-mail address). In case of an e-mail whose recipient is a distribution list (i.e., a mailing list), the e-mail is forwarded to each of the members of the list.

Additional rules can be created directly on Postfix from the CLI. Examples of restriction rules can be found directly in Postfix documentation, for example in Postfix Standard Configuration Examples. More examples, depending on the use case, can be found in the official Postfix documentation.

Server-side Attachment Management#

Global e-mail attachment settings allow you to specify global rules for handling attachments of an e-mail message.

Modify list of blocked file extensions

You can set rules at COS-level and also for individual accounts. When attachment settings are configured in Global Settings, the global rule takes precedence over COS and Account settings.

A list of formats (extensions) can be created via CLI to restrict the attachments allowed.

Warning

All files whose extension is in the list will never reach the recipient.

For example, to block .exe filex, use command

# carbonio prov mcf +zimbraMtaBlockedExtension "exe"

Hint

Only one format/extension at a time can be specified.

Manage attachments’ size

It is possible to limit both the size of a message and its attachment and their individual sizes.

The total size of the message can be set for each MTA server directly on the Carbonio Admin Panel, in the Tuning section under Admin Panel ‣ MTA ‣ Advanced (see documentation).

The maximum size of each attachment can be set by the CLI for each user, CoS, or domain issuing as the zextras user

zextras$ carbonio prov ma alice@example.com zimbraFileUploadMaxSizePerFile 1048574

This command prevents Alice to sent an attachment larger that 10Mb.

Management of a COS#

Each account on Carbonio is assigned a COS, a global object that is not restricted to a particular domain or set of domains.

The COS assigned to an account determines the default attributes for that account and the features to be enabled or not for it. The COS controls mailbox quotas, message lifetime, password restrictions, attachment blocking, and server pool usage.

You can create and edit the classes of services via CLI and soon also via the new Carbonio Admin Panel, in which the tasks of COS management will feature an helpful wizard that guides the Administrator through the creation process.

# carbonio prov createCos {name} [attribute value ...]

All the attributes that need to be customised can be either added at the end of the base command above as [ attribute value ] pairs, or at a later point with the following command:

# carbonio prov modifyCos {name} [attribute value ...]