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 enter a domain name. This is all that is required.

2.2 Basic information

You enter the most common options here.

Fall back destination

Normally, when an email message is sent to an account on a virtual email domain, the following processing is done:

• Check for an alias of that name. If there is one, send the message to each member of the alias list. (Aliases may point to other aliases.)
• If no alias is found, then the user list of the virtual domain is checked. The email is appended to the folder of the corresponding user if a match is found.
• If no alias or username matches the intended recipient, the message is rejected and the sender will receive an error message.

However, if the fallback field is defined, the email will be sent to the fallback address instead. This is also known as a "catch-all" address since it will catch any messages that don't have an alias or username match. The fallback address may be:

Empty

This is the default case. The message is rejected and the sender will receive a 'bounced' message.

another_user@another_domain

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

@another_domain

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

account

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

| some commands and arguments

The message is sent to the command. Token replacement is performed on the command. See below.

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's inbox. This is the default for the entire 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 joe@domain.com or joe.who@domain.com.

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 returned to the sender.

Users can't retrieve their messages

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

2.4 Administrator

You can grant administrator privilege to any normal user (Linux users) of the server. Often, we do not want to create Linux accounts on the server at all.

This section allows you to define a password allowing a pseudo-user called admin@the-domain to administer user accounts and aliases in this virtual email domain. This only works in WEB mode ( You need a linux account to use the other user interfaces anyway).

So for a virtual email domain foo.com, the pseudo-account is admin@foo.com.

Enable co-administration

You can turn on an off co-administration privilege. This only affects the pseudo-user. Other linuxconf privileges are not affected (The ones granted to linux users).

Co-administrator password

You enter the password twice. If you leave the fields empty, the current password is preserved.

2.5 Extra aliases files

Each virtual domain implicitly has 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.

2.6 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 foo.net and later register foo.com. By using a domain alias, both domains will be equivalent.