Domains

Domain names are used to identify the mail server on the internet (or LAN). Domain names are used when you connect to the mail server to receive mail (e.g. by POP3), and when other mail servers connect to the mail server to send it mail.

Domain names are used together with DNS services to send and receive mail.

ISMail supports either a single or multiple domain names. The initial domain name (primary domain) must always be specified and is used as the default domain. Additional domain names may also be specified, but they are optional.

If the mail server is connected to the internet, then Registered internet domain names must be used. If the mail server is only connected to a local area network (LAN), then a name known to the DNS or other directory services used by the LAN can be used.

Important note about domain naming: ISMail domain names should always be 'plain' domain names, such as 'yourdomain.com'. Domain aliases, such as 'www.yourdomain.com' or 'smtp.yourdomain.com' should not be used, even if there are DNS MX records which refer to one or more of these names. The reason is that all mail accounts are addressed using ISMail domain names. So, ISMail accounts 'user1' and 'user2' on domain 'yourdomain.com' would be addressed as 'user1@yourdomain.com' and 'user2@yourdomain.com'. However, the same users on a domain named 'www.yourdomain.com' would be addressed as 'user1@www.yourdomain.com' and 'user2@www.yourdomain.com' which are generally not the email addresses desired.

Primary Domain

The primary domain name must always be present, and is used as the default domain name for the server.

Setting the Primary Domain

To set the primary domain:

  1. Right-click the program icon located in the lower-right portion of the screen (notification area of system tray), and select 'Open'.
  2. Select the 'Domain' tab.
  3. Enter the primary domain name.
  4. Click 'Apply'.

Multiple Domains

A single copy of ISMail may be used to provide mail services for one or more domain names.

Each domain must be set to one of two types:

  • Virtual domain: domain can use any IP address on the server to send messages.
  • IP-based domain: domain can only use the IP address specified to send messages. If that IP is unavailable, then any available IP address will be used.

When setting up multiple domains, each domain name should first be configured in ISMail, and then accounts added (in ISMail) for that domain name. Then, mail accounts in any email client programs should be setup depending on the type of domain (see Accounts).

Virtual Domains

ISMail can be configured to allow domains to share IP addresses. This feature can be used with one or more domains, on machines with one or more IP addresses, and on machines with dynamic IP addresses.

With virtual domains, the operating system selects the IP address to use to send any given message.

IP-based Domains

ISMail can be configured to assign domains to a specific IP addresses. This feature can be used with one or more domains, and on machines with one or more IP addresses, but not on machines with dynamic IP addresses since there is no way to update the domain's IP address in ISMail.

On systems with only 1 IP address, IP-based and virtual domains are nearly identical.

If a machine has only 1 IP address, then all domains will use this IP address regardless of if they are IP-based or virtual domains.

Domain 'Greeting' Messages

The primary ISMail domain name will be displayed in the SMTP 'greeting' message for all virtual domains.

An IP-based domain name will be displayed for incoming connections on the IP address of IP-based domains.

Configuring Multiple Domains

To add virtual domains:

  1. Right-click the program icon located in the lower-right portion of the screen (notification area of system tray), and select 'Open'.
  2. Select the 'Multiple Domains' tab.
  3. Click 'Add'.
  4. Enter a Domain Name, and a (text) Description.
  5. In the 'Address Mapping' box, select 'Virtual'.
  6. Click 'OK.'.

To add IP-based domains:

  1. Right-click the program icon located in the lower-right portion of the screen (notification area of system tray), and select 'Open'.
  2. Select the 'Multiple Domains' tab.
  3. Click 'Add'.
  4. Enter a Domain Name, and a (text) Description.
  5. In the 'Address Mapping' box, select 'Address'. Enter an IP address.
  6. Click 'OK'.

To change a virtual domain to an IP-based domain:

  1. Select the 'Multiple Domains' tab.
  2. Select the domain to change.
  3. Click 'Edit'.
  4. In the 'Address Mapping' box, select 'Address'. Enter an IP address.
  5. Click 'OK'.

To change an IP-based domain to a virtual domain:

  1. Select the 'Multiple Domains' tab.
  2. Select the domain to change.
  3. Click 'Edit'.
  4. In the 'Address Mapping' box, select 'Virtual'.
  5. Click 'OK'.

To remove a domain:

  1. Select the 'Multiple Domains' tab.
  2. Select the domain to remove..
  3. Click 'Remove'.
  4. Click 'OK'.