This question relates to managing more than one mail domain on a single server with a limited number of IP addresses.
The POP3 and IMAP4 protocols have a failing when supporting more than one domain from the same IP address. Due to the way that the specifications were written, it is not possible for the mail server to manage more than one domain per IP address.
Virtual domains overcome this limitation imposed by the standards by providing two choices. Firstly by using a “postfix” to the user name to indicate the correct domain OR by including the domain name in the user name itself. Which of these you use depends entirely on the ability of the mail clients to support the work-around.
When a virtual domain is set up, a "Postfix" is required. This differentiates the mailboxes in that virtual domain from those in other domains run by the mail server.
Do I need to supply this "postfix" to the users of this virtual domain so that they can log into their pop accounts?
Consider the case of a full domain of "full.dom" (mail.full.dom) and your new virtual domain of "virtual.dom" with a postfix of "my" for a user called John.
In order to receive email your users/customers should give their email address as John@virtual.dom. EMail will automatically be routed to John’s email account correctly when it arrives.
Users/customers have a choice of how to collect email:
- For POP3/IMAP4, use a user name of "John@virtual.dom" and connect to the mail server at "mail.full.dom". The system will identify the correct account and provide access to the correct mailbox. NOTE: Some mail clients may not allow you to enter &Quot;firstname.lastname@example.org" as a user name. In this case, the next solution should be used.
- For POP3/IMAP4, use a user name of "John-my" and connect to the mail server at "mail.full.dom". The system will identify that the account is John@virtual.dom and provide access to the correct mailbox.
- For GMS Webmail, use the account name of “John@virtual.dom” when connecting to any IP address managed by the mail server.
Keywords:virtual domain pop imap logon login log postfix