Adding a Suffix based Virtual domain

Adding a Suffix based Virtual domain
As an alternative to having multiple IP numbers, virtual domains can be set up by asking users of the virtual domain to connect to the POP server with a suffix on the end of their username. E.g. using POP login usernames of the form,
fred/jds

To make a virtual domain a 'suffix based vdomain', you add a vdomain line to dmail.conf as with an IP based vdomain, but replace the IP Address with the unique suffix for that domain.

For example, we might have:

vdomain johns /jds johns.server.com /var/spool/mail/johnsusers
where '/jds' is the suffix.

If DPOP finds this suffix on any user POP login name, it will remove the suffix and treat the user as belonging to the vdomain of the vdomain line that it matches.

DPOP will do this no matter what IP address the user connects to.

See IP Address based virtual domains for explanations of the other values of the vdomain setting beside the suffix.

Note: the suffix includes any separator character, in the example above it was '/'.

Making suffixes more convenient:

Obviously, this form of virtual domains can be an inconvenience to users if they have to change their client software settings to connect as 'username_suffix' instead of just 'username'. It can also be a little confusing to customers.

1. One common way to get around this is to make the suffix, '@domain' so that the user can use their email address as their POP login, e.g. if we changed the vdomain line above to,

vdomain johns @johns.server.com johns.server.com /var/spool/mail/johnsusers
Then the suffix is now, '@johns.server.com', so the user fred would login to the POP server with,
fred@johns.server.com

NB: The only problem with this is that some email clients won't let you enter a username with an @ in it. The notable example is Netscape Mail, although the word is that they have realised their mistake and will change that in an upcoming version.

We have just been given instructions on how to allow the @ character to be used in netscape.
1. Close Netscape
2. Edit /program files/netscape/user/prefs.js (right click - open with notepad)
3. Add new line:
user_pref("mail.allow_at_sign_in_user_name", true);
4. Save file
5. Open Netscape



So, if you are going to do this, and have users connecting directly to the POP server with any client, then we suggest you create a second vdomain line for the same domain. The second vdomain line must come after the main vdomain line in dmail.conf. It differs from the first only in that it specifies a different suffix.

So using our example above, you can change,

vdomain johns /jds johns.server.com /var/spool/mail/johnsusers
to,

vdomain johns /jds johns.server.com /var/spool/mail/johnsusers
vdomain johns @johns.server.com johns.server.com /var/spool/mail/johnsusers

NOTE: The above example defines ONE virtual domain, so the same PREFIX 'johns' is used for all three, the prefix must not be the same for different virtual domains, and must not include an underscore character

2. Another common way to make suffixes more 'transparent' is to hide them all together. If you are using any of our Web to EMail gateway products like CWMail or WebMail, they have an ini setting called 'suffix'. You can use that setting to make them automatically add the suffix to the username given by the user on login. So if the user always collects their mail with the web interface, they don't ever need to know about the suffix.

We recommend the use of suffix based vdomains when using the web interfaces.

Remember that whether a vdomain is IP address based or suffix based, the form of the username in the database is independent. So you can easily change a domain from one to another at a later date. For some changes you would need to alter your DNS entries as well.


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http://netwinsite.com/dmail/domains.htm