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2. Virtual domain definition dialog

To create a new virtual email domain, you must complete a single dialog. There are other tasks to do that are related to the DNS and IP aliases. They are described in other sections of this help tool. We will describe here the main dialog.

2.1 A name

You must give a domain name. This is all that is required.

2.2 Basic information

You enter here the most common options.

Fall back destination

This is an optional field. Normally, when an email message is sent to an account on a virtual email domain, the following processing is done.

If the fallback field is defined, the email will be sent to the fallback address instead. The fallback address may be:


This is the default case. The message is rejected.


The message is sent to a specific user of another domain.


The message is sent to the same target account, but in another domain. For example, email sent to unknown@this_domain will be forward to unknown@another_domain.


The message is sent to another account of the same domain. This account may be an alias.

Allocate UID from

Normally, user IDs for virtual email accounts start at 60,000 for all domains. You can control the start of the allocation range if you wish. This is mainly used for people wanting to play with disk quotas. Note that the vdeliver program can limit the size of the user inbox as well.

Limit user inbox to (k)

Enter the limit, in kilobytes, for the user inbox. This is the default for the domain. You can override it user by user if needed.

The default is no limit.

2.3 Features

Maximum number of users

You can limit the number of accounts in a domain. Co-administrators won't be allowed to create more than this number. By default, there is no limit.

Match user full name

When enabled, the delivery agent will try to match the user's full name. It replaces the spaces in the full name by dots and tries to match against this. So, user joe, with full name "joe who" may receive email as or

Filter program + args (opt)

You can specify an optional program which will filter the messages when they are appended to the user inbox folder. The filtering may be used to check for some bad content (perhaps a virus?).

The filtering program receives the message on its standard input and writes the modified message (or nothing) on its standard output.

You can specify some arguments as well. Specify the full path of the filter.

Incoming mail are rejected

You can turn off incoming mail for the whole domain. Mail will be rejected and an error message will be return to the sender.

Users can't retrieve their messages

This locks the POP-3 and IMAP services for this domain.

2.4 Extra aliases files

Each virtual domain has implicitly an aliases file named /etc/vmail/aliases.domain where domain is the domain name. You can define two more, if needed. They will be used by the vdeliver program. The implicit one has the highest priority. vdeliver looks in the first and then in the second until a match is found.

Note that, like the normal aliases (/etc/aliases) processed by sendmail, alias definitions may point to another alias and so on. Mailing lists may be defined, etc...

Alias files are maintained by the same dialog as normal sendmail aliases, and as such, offer the same capabilities.

2.5 Aliases for this domain

It is possible to provide several domain names pointing to the same user pool. You can add as many as needed. For example, one may define the virtual domain and later register By using a domain alias, both domains will be equivalent.

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