Secondary Domains

In addition to the main domain, the Server can handle multiple Secondary Domains, each with its own set of user accounts.

Even if you want to serve several domains with your Server, you may still use one main domain, mapping the addresses in other domains onto main domain accounts. See the Serving POP and IMAP Clients document.

You may want to use Secondary domains if:

or


Displaying Secondary Domains List

To display the list of registered Secondary Domains, use a Web browser and enter the Domains section. You should be connected as the Postmaster or you should have the Can Modify User Accounts access rights to create and remove domains and to modify domain options enabled.

Filter:

To select domains by name, type a string into the Filter field, and click the Display button: only the domains with names containing the specified string will be displayed.

Each line in the list contains an domain name, the number of currently opened accounts in that domain, the total number of times accounts in the domain have been opened since the Server last restart, and the last time an account in that domain was accessed:

Domain

Open Accounts

Total Hits

Last Hit

 
f-client.com 18 178 21-03-1998 options
client.company.org 34 2056 18:09:43 options

2 of 23 name(s) selected

Click a domain name to view the accounts in that domain.

Click the word options in the last column to view and update domain options.


Creating a New Secondary Domain

Type a new domain name into the field on the right side of the Create Domain button.

The Server checks the IP addresses of all secondary domains. The A-records for all its secondary domains should exist in the Domain Name System. These records should specify IP address(es) that are among the IP addresses of the Server computer.

Click the Create Domain button. When a new domain is created, its name appears in the Secondary Domains list.


Specifying Domain Options

Main domain and all Secondary Domains have some options.

To open the Domain Options page in your browser, either click the Options link in the Secondary Domains list, or click the Domain Options link in the Account List of that domain.

Account Log:

Mailbox Log:

Accounts

The Account Log option allows you to specify how the account-level operations (account open/close, password verifications, mailbox creating/removing, size updates, etc) are recorded. Log records created for account-related events have the ACCOUNT tag.

The Mailbox Log option allows you to specify how the mailbox-level operations (message storing/removing, message status updating, etc.) are recorded. Log records created for mailbox-related events have the MAILBOX tag.

You can also specify how messages to unknown accounts should be processed (see below).

When the Domain Options are modified, click the Update button. The page should appear again, displaying the Updated marker.

You can click the Accounts link to switch to the list of the domain accounts.


Processing Mail To Unknown Accounts

When a message comes addressed to the main server domain or to one of subdomains and there it is addressed to an account unknown in that domain, the Server (actually, the Local Delivery module) processes it as specified in that Domain Options.

Mail to Unknown Accounts

is

Rejected
the address is rejected; if message is being received via SMTP, the address is not accepted, and if it was the only recipient address in the message, the message is not received at all.
Discarded
the address is routed to NULL. The message is considered "delivered" immediately.
Rerouted to:
the address is changed to the E-mail specified in the text field, and the Router restarts trying to route this new address. Please note that you specify an E-mail address, not an account name there. So, if you specify Postmaster in a Secondary Domain Reroute To: option, the message will be routed to the Postmaster account in the Main Domain, not to the Postmaster account in that Secondary Domain.
Accepted and Bounced
the same as Rejected, but account existence is not checked at the Router phase. In case of SMTP receiving, it means that any address in this domain is accepted. Then, if the Local Delivery module fails to find the addressed account, the message is rejected and an error report is sent back to the sender.


Sending Mail To All Accounts in the Domain

The administrator can enable the special virtual account "all" used to send messages to all accounts registered in the domain.

Mail to <all@domainname>
is

Rejected
the "all" account is disabled, messages to <all@domainname> are rejected.
Distributed
a message sent to the <all@domainname> is sent to all accounts in the domainname domain.
Distributed for Clients Only
a message sent to the <all@domainname> is sent to all accounts in the domainname domain only if the message has been received from a "trusted" source: via SMTP - from the "client hosts", via RPOP, via POP using the XTND XMIT method, via UUCP from the trusted hosts, etc.


Renaming Secondary Domains

If you want to rename a Secondary Domain, open its Domain Options page with a Web browser, and enter a new account name into the New Domain Name field. Click the Rename Domain button.

If there is no other domain with the same name as the specified new domain name, the domain is renamed and its Domain Options page should reappear on the screen under the new name.

You cannot rename a domain when any of its accounts are in use.


Removing Secondary Domains

If you want to remove a Secondary Domain, open its Domain Options page with a Web browser, and click the Remove Domain button. The confirmation page should appear. If the Empty Domains Only option is selected, a Secondary Domain is removed only if there are no accounts in it. Otherwise, all Domain Accounts are permanently removed, too.

If you confirm the action, the selected domain, its options, and all its accounts will be permanently removed from the Server disks.

You cannot remove a domain when any of its accounts are in use.


Accessing Accounts in Secondary Domains

When a user connects to the Server using a POP, IMAP or HTTP mailer, and provides a name and a password, the Server tries to find a Secondary Domain for that name.

First, the server checks if the provided name is a "full account name", i.e. if it is in the account%domain.name or account@domain.name form. If the name is in one of the these forms, the Server tries to find an account in the specified Secondary Domain, or in the Main Domain, if the specified domain name is the Server domain name.

Example:
A user open her mailer and specifies susan@client1.com as her E-mail address. She then checks the Send Full Account Name option in her mailer. The mailer connects to the Server, and sends susan%client1.com as the user name. The Server detects a "full account name" and opens the account susan in the client1.com domain.

If the provided name is a simple account name, the server checks the IP address to which the client has connected. If that IP address is not an address of the Server domain name, but is an address of one of the registered Secondary domains, the Server opens the specified account in that domain. Otherwise, it opens an account in the Main Domain.

Example:
your Server has 4 IP addresses:
206.40.74.194, 206.40.74.195, 206.40.74.196, 206.40.74.197
your Server domain name is mycompany.com, the created secondary domains are client1.com and client2.com.
the DNS A record for the mycompany.com lists the addresses 206.40.74.194 and 206.40.74.195.
the DNS A record for client1.com points to the address 206.40.74.196
the DNS A record for client2.com points to the address 206.40.74.197
 
Now, a user opens her mailer and specifies susan@client1.com as her E-mail address. The mailer uses client1.com as the name of the (POP/IMAP) server, converts that name into the 206.40.74.196 address, connects to that address, and sends susan as the user name.
The Server detects that the client has connected to the address that is not one of its Main domain addresses, but is one of its client1.com addresses. As a result, the account susan is opened in the client1.com domain, not in the Main Domain.