Version 5.1
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When an Account is created, its INBOX Mailbox is automatically created. The system and/or domain administrator can specify additional Mailboxes to be created at that time.
A user can create a Mailbox using an IMAP, MAPI, or XIMSS mailer application or using the WebUser Interface.
Mailboxes can be "nested": for any Mailbox "A" you can create a sub-Mailbox "B" - in the same way as you can created a file directory inside some other file directory. The CommuniGate Pro Server uses the slash (/) symbol as the hierarchy separator: INBOX/important is the name of the sub-Mailbox important "inside" the INBOX Mailbox.
CommuniGate Pro allows you to store messages in some Mailbox X and at the same time you can create sub-Mailboxes X/Y, X/Z for that Mailbox. This feature is implemented by providing two "invisible" Mailbox entities - one for storing messages, one - for serving as a "directory" for the nested Mailboxes. The "directory" entity is created automatically, as soon as you try to create the first sub-Mailbox. You can, though, create the "directory" entity without creating the "mail storage" entity: use the ABCDEF/ name as the new Mailbox name to create only the directory entity with the ABCDEF name. The name ABCDEF will be listed, but will not be "selectable" - and you will not be able to store messages in the ABCDEF Mailbox. You can later create the regular ABCDEF Mailbox and the "storage" entity for your ABCDEF Mailbox name will be added.
It is impossible to delete the INBOX Mailbox. You can rename the INBOX Mailbox, though. In this case a new empty INBOX Mailbox will be created automatically.
Mailbox names are case-sensitive. Some file systems (NTFS, for example) provide case-insensitive file naming conventions. When these file systems are used for CommuniGate Pro Account/Mailbox storage, the Mailbox names are still case-sensitive, but you cannot create two Mailboxes with names that differ in case only. The INBOX Mailbox name is an exception: it is always a case-insensitive name.
Messages in Mailboxes have individual flags. These flags can be set when the message is being stored in the Mailbox, and they can be updated using Mailbox access protocols and methods, such as IMAP, MAPI, XIMSS, WebUser Interface, Real-Time Applications.
Some flags are set automatically, even when the access protocol used does not support flag modification. For example, the Seen flag is set automatically when the message is being read using the POP protocol RETR command.
Several components (such as Automated Rule, CG/PL programs, etc.) can access message flags by name. They can also use "negative names" to instruct the server to reset a certain flag or to look for messages that do not have that flag set.
The following table lists the supported message flags along with their IMAP and Negative names:| Name | Description | IMAP Name | Negative Name |
|---|---|---|---|
| Seen | This flag is set when the message was read by a client. It can be set automatically as a result of certain Mailbox access operations, and it can be set and reset explicitly with mail client applications. | \Seen | Unseen |
| Read | same as Seen | Unread | |
| Answered | This flag is set when a reply was sent for this message. This flag is explicitly set and reset with mail client applications. | \Answered | Unanswered |
| Flagged | This flag is set to attach a "flag" to the message (for example, a mail client can show this message to the user as an important one). This flag is explicitly set and reset with mail client applications. | \Flagged | Unflagged |
| Draft | This flag is set for messages that have not been sent yet. It tells a mail client that it can open and edit this message. This flag is explicitly set and reset with mail client applications. | \Draft | Undraft |
| Deleted | This flag is set for messages that were marked for deletion. Some mail clients allow users to mark some Mailbox messages first, and then delete ("expunge") all marked messages from the Mailbox. This flag is explicitly set and reset with mail client applications. | \Deleted | Undeleted |
| Redirected | This flag is set when a copy of the message was sent (redirected) to someone. This flag is explicitly set and reset with mail client applications. | $Forwarded | NotRedirected |
| MDNSent | This flag is set when an MDN ("read report") for the message has been sent. This flag helps mail clients to send only one MDN report for each message. This flag is explicitly set and reset with mail client applications. | $MDNSent | NoMDNSent |
| Hidden | Messages with this flag set are visible only to the Mailbox Account owner and
to those users who have the Admin Access Right for this Mailbox.
This flag allows users to grant access to their Mailboxes to others while keeping certain messages private (hidden). |
$Hidden | NotHidden |
| Service | Messages with this flag set are not visible to IMAP or POP clients.
MAPI clients can use this flag to create service items invisible to users (such as Mailbox forms). |
$Service | NotService |
| Media | If this flag is set, the message is treated as containing some "media" (audio/video) data. | $Media | NotMedia |
| Junk | If this flag is set, the message is treated as "junk" (spam). | Junk | NotJunk |
| Label1 | Custom flag. | $Label1 | NotLabel1 |
| Label3 | Custom flag. | $Label3 | NotLabel3 |
| Label1 | Custom flag. | $Label1 | NotLabel1 |
The CommuniGate Pro Server maintains an Access Control List (ACL) for every Mailbox it creates.
Each element of the Access Control List contains a name and a set of Mailbox access rights
granted to that name.
The Access Control Lists are used to control the Foreign Mailbox Access feature that allows one Account user to access Mailboxes in other Accounts.
An ACL element name can be:
An ACL element name can have a + or a - prefix.
Account owners always have all access rights to all Mailboxes in their own Accounts.
For any other someaccount Account, the effective access rights are checked.
The effective access rights are calculated in several steps:A Server Administrator with the All Users access right has all access rights to all Mailboxes in all Server or Cluster Accounts.
Domain Administrators with the CanViewMailboxes access right have all access rights for all Mailboxes in their Domains.
The following Mailbox access rights are supported:When a sub-Mailbox is created, it inherits the ACL of the "parent" Mailbox. This means that if you create the INBOX/sales Mailbox, it is created with the same ACL as specified for the INBOX Mailbox.
The Access Control Lists can be set and modified using the WebUser Interface, a XIMSS, a MAPI, or a decent IMAP client.
In order to be able to delete a foreign Mailbox, a user should have:When granting access rights, the real Account names, not Account Aliases should be used. If an Account j.smith has two aliases john.smith and jonny, the access rights should be granted to the name j.smith.
| anyone@ | Lookup, Select, Seen | |
| -john | Select, Seen | |
| +susan | Delete |
| anyone@company2.com | Lookup, Select, Seen | |
| -john@company2.com | Lookup, Select, Seen | |
| susan@company3.com | Lookup, Select, Delete |
CommuniGate Pro stores received messages in Account Mailboxes. The server supports several Mailbox formats, and the Mailbox type is defined by the Mailbox file (or directory) name extension.
For single-Mailbox Accounts, the Mailbox type is specified when the Account is created.
Each multi-Mailbox Account has a setting that specifies the default type for all new Mailboxes created in this Account. A user can explicitly specify the Mailbox type creating a Mailbox in a multi-Mailbox Account: if the maibox name is specified as name.extension, then the Mailbox name of the extension type is created.
If a Mailbox file has been copied from an old system, or when it is used as an External INBOX and old applications can add messages to this Mailbox, some messages may have no "comment;" part. CommuniGate Pro allows a user to work with such messages, but it does not store message flags if they were modified, and it does not remember the message UIDs between sessions. The simplest solution is to copy such messages to a different Mailbox and then copy them back to the original Mailbox - the copy operation places the correct information into the From-line.
When a message is being stored in the .mbox-type Mailbox, all message lines are checked. If there is an empty line followed with the line starting with the letters From, the '>' symbol is inserted before the letter F.
The TextMailbox Mailboxes become less effective as their size grows. When a TextMailbox is being opened, it has to be parsed, in order to detect message boundaries and retrieve the UID, flags, and other per-message information. When some messages are being deleted from the middle of a TextMailbox Mailbox, the Server has to copy the remaining messages data, compressing the Mailbox. To make these processes more efficient, the CommuniGate Pro server can deal with Mailbox data in large chunks. A special semaphore object limits the number of buffers allocated for large Mailbox processing. Changing this parameter can change the overall large Mailbox access (you may want to increase or decrease it, depending on the OS and file system you use).
To improve TextMailbox opening speed, the CommuniGate Pro can maintain a Mailbox index (.bdx) file
alongside the TextMailbox Mailbox file. If the index file exists, the Server reads it instead of parsing the
entire Mailbox file. CommuniGate Pro automatically creates an index file when it the Mailbox file size exceeds the
specified limit. The Server removes the index file if the Mailbox becomes smaller than that limit.
The Index file is created when any message in the Mailbox is modified or deleted. If new messages have been
added to the Mailbox, but the Mailbox has not been opened, or it has been only read without any flag modification,
the Index file may not be created.
Use the WebAdmin Interface to specify the TextMailbox Manager settings. Open the General pages in the Settings realm, and find the TextMailbox Manager panel on the Others page:
Mailboxes with this extension are file directories. Each Mailbox message is stored as a separate file in the Mailbox directory.
The message file name has the following format:Note:On the Unix platforms, the .mdir Mailboxes implement the shared storage model: if the same message is directed to many Accounts/Mailboxes, only one message file is created, and a hard link to that file is placed into each Mailbox directory. When a message is removed from all Mailboxes, the file is automatically deleted by the OS.
Note: most of freeware mail systems use either the mbox-like or mdir-like formats, and designers of those systems make various claims about the advntages of the formats they have selected. It is very important to remember that:
Note: the .mbox format is more efficient than .mdir in most cases, this is why this format is used as the default one. The .mdir format is recommended only for those Mailboxes that contain many (20 or more) large (100K or more) messages. If a user has a Proposals Mailbox where she stores all messages with attached documents, each 200-500K in size, then this Mailbox may work faster if it is created in the .mdir format.
Each Mailbox can have a Class attribute. This attribute specifies the type of the information this Mailbox is created for: Calendar, Contacts, Tasks, Notes, etc. If a Mailbox does not contain the Class attribute, it means that it is created to store regular E-mail messages.
The Mailbox Class does not restrict the types of data that can be stored in the Mailbox: E-mail and Contacts messages can be stored in Mailboxes with the Tasks Class, Notes messages can be stored in Calendar Class Mailboxes, etc. The Mailbox Class information is used with the advanced user interfaces (WebUser, MAPI) to present the Mailbox content in the proper format.
When a Mailbox is created with an advanced client interface, the interface can set the Mailbox Class. Mailbox Classes can also be updated using the CommuniGate Pro CLI/API.
Each Mailbox can have the Locked attribute. If this attribute is set, the Mailbox cannot be deleted or renamed.
A locked Mailbox can be deleted or renamed together with its parent Mailbox, if the parent Mailbox itself is not locked.
You can specify the Locked attribute for the Mailboxes created using the Account Template. The Mailbox Locked attribute can also be updated using the CommuniGate Pro CLI/API.
Every Account has a setting that specifies the default format for new Mailboxes that can be created in this Account.
The Account user can explicitly specify the storage format for a new Mailbox by adding the format extension to the new Mailbox name. If a user tells the CommuniGate Pro Server to create the newmailbox.mdir Mailbox, the .mdir-formatted Mailbox newmailbox is created.
The CommuniGate Pro Server allows an Account user to subscribe to some Mailboxes. The Account Mailbox subscription is a simple list of Mailbox names. This list is not used by the Server itself - the Server just stores one subscription list for each Account.
Many IMAP mailers use the Account subscription list and show only the Mailboxes the Account is subscribed to. The WebUser Interface can also be configured to show only the subscribed Mailboxes.
You can modify the Account subscription either via a decent IMAP mailer, or using the WebUser Interface.
You can use the Account Mailbox subscription to make some not-so-decent IMAP mailers access foreign Mailboxes: make sure that your IMAP client is configured to use the Account Mailbox subscription, and add the desired foreign Mailbox name into the subscription list.
Note:Some IMAP mailers tend to rebuild Account subscription lists: they empty the subscription, and then subscribe you to all Mailboxes in your own Account.
The Account Mailbox subscription is stored in the Account .info service file.
Many IMAP clients (such as Microsoft Outlook and Outlook Express) cannot handle foreign Mailboxes directly, and they cannot use the Account Mailbox subscription to access foreign Mailboxes.
Mailbox aliases can be used to let these IMAP clients access foreign Mailboxes.
Mailbox alias is a name associated with some [foreign] Mailbox name. For example, you can create a Mailbox alias salesBox for the ~sales/INBOX Mailbox name. You will see the salesBox Mailbox in your IMAP mailer, but in reality this will be the INBOX Mailbox in the sales Account.
Mailbox aliases can be created only on the topmost level of the Account Mailbox hierarchy, that means that the Mailbox alias name cannot contain the slash (/) symbol.
Mailbox aliases can contain just the name of the foreign Account (~accountName). Such an alias provides access to all accessible Mailboxes in that foreign Account. The Mailbox alias itself is presented as an unselectable Mailbox name.
Sample configuration:The owner of the Account chief has granted "lookup" and other access rights for his Mailboxes INBOX and Pending to the assistant Account.
The user assistant has created the Mailbox alias boss pointing to ~chief.
When the user assistant connects to her Account using any IMAP client or the WebUser Interface, she sees all her own Mailboxes, the unselectable Mailbox boss, and also the boss/INBOX and boss/Pending Mailboxes.
If the user cheif creates a new Mailbox Urgent in his Account and grants access rights for that Mailbox to the assistant Account, the user assistant will immediately see the new Mailbox as the boss/Urgent Mailbox.
The CommuniGate Pro Server allows several client applications to connect, open the same Mailbox, and read and modify the Mailbox data at the same time.
The CommuniGate Pro multithreaded design allows the Server to synchronize client activities without using OS-level file locks and it does not require a client to wait till all other clients close the Mailbox.
Simultaneous Access means that:Clients accessing the same Mailbox can use the same or different Mailbox access protocols - POP, IMAP, MAPI, WebUser, or XIMSS Interface.
Simultaneous Access is supported for all Mailbox types implemented in the CommuniGate Pro software.
This feature allows you to work with your Mailbox from several workstations, and it lets a group of people (i.e. the sales department) process messages in one centralized Mailbox.
The CommuniGate Pro access system allows an Account user to access Mailboxes in other Accounts.
Access to these foreign Mailboxes (also called shared Mailboxes) is controlled via
the Mailbox Access Control Lists.
To access a Mailbox in a different Account, the Mailbox name should be specified as ~accountname/mailboxname. For example, to access the INBOX Mailbox in the Boss Account, the Mailbox name should be specified as ~Boss/INBOX .
If there are several local domains on the Server, Mailboxes in a different domain can be accessed by specifying full Account names. To access the LIST/reports Mailbox in the Account ListMaster in the client.com domain, the Mailbox name should be specified as ~ListMaster@client.com/LIST/reports.
Account names specified after the "~" sign are processed with the Router, so Account Alias names can be used instead of the real Account names, and all Routing Table rules are applied.
Very often Foreign Mailboxes are used:CommuniGate Pro can provide "public" Mailboxes, too. This can be done by creating an Account public, and assigning public Access rights to its Mailboxes. Usually, each group of public Mailboxes is managed by some administrator, who is not required to be a CommuniGate Pro administrator.
A CommuniGate Pro Server administrator should create the public Account, log into that Account using the WebUser Interface or a decent IMAP client, create some public Mailboxes, and grant administration rights to regular users that will administer these public Mailboxes. Those users will then grant access rights to other users, create sub-Mailboxes, and perform other administrative tasks.
For example, a public Mailbox administrator can use Automated Rules to copy certain incoming messages directly into some public Mailbox.
Some IMAP clients (such as Microsoft Outlook and Outlook Express) do not support foreign Mailboxes at all. To let those clients access shared Mailboxes in other Accounts, Mailbox Aliases can be used.
On some systems users have direct (login) access to the mail server computer, and some of them get used to Local Mailers - mail, elm, and others. Local Mailers do not use any network protocol to access mailboxes. Instead, those programs read and modify mailbox files directly, via the file system.
The CommuniGate Pro allows you to create Accounts with External INBOX Mailboxes. These Mailboxes are stored not inside the CommuniGate Pro base directory, but in the system directory known to the legacy mailer applications.
Since these INBOX files can be read and modified directly, bypassing the CommuniGate Pro protocols and modules, the Server needs to synchronize its activity with legacy mail applications using OS file locking features - either FileLevel locks or FileRange locks.
On Unix systems the FileLevel locks are known as flock operations, and RangeLevel locks are known as fcntl operations. Check with your OS manual to see which method the legacy mailers use on your system, and configure the CommuniGate Pro Server to use that method. For systems that support only one file locking mechanism (MS Windows, Sun Solaris, and some other systems), selecting either method selects that mechanism.
You should use External Mailboxes only when absolutely necessary, because:If you have to support Local Mailer compatibility for all or some Accounts in a Domain (usually - in the Main Domain), you should specify the External Mailboxes settings for that Domain.
When you create an Account that has an External INBOX, the Server checks if the Account INBOX file already exists in the specified location and creates one if the Mailbox file is absent.
When you delete an Account that has an external INBOX, the Server does NOT remove the INBOX Mailbox file.