Virtmaps - Providing E-Mail for Virtual Subhosts

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Virtmaps - Providing E-Mail for Virtual Subhosts
In order to provide e-mail for your Virtual Subhost customers, you will probably use the Virtual Private Server "virtmaps" feature. This is a proprietary feature (only available on our Virtual Private Servers) that we have added to sendmail, the underlying program which handles all of your Virtual Private Server E-Mail.

Why Virtmaps?
An HTTP/1.1 compliant web server (like your Virtual Private Server Apache Web Server) can detect Virtual Subhost domains when an HTTP request is made, and it sends back the corresponding content to the client. An SMTP server without the virtmaps feature cannot detect Virtual Subhost domains. It can only see that subhost1.com and subhost2.com resolve to the same IP address. So, to the SMTP server, webmaster@subhost1.com and webmaster@subhost2.com are the same thing.

The virtmaps feature provides your Virtual Private Server SMTP server a method to detect the domain name of an incoming e-mail. Then, e-mail to similar usernames but different domain names can be routed differently. This allows you to configure similar domain-specific e-mail aliases (such as webmaster@subhost1.com and webmaster@subhost2.com) and map them to different e-mail addresses. The virtmaps feature also supports wild card mapping, so that any e-mail sent to a non-existing e-mail address is delivered to a "catch-all" e-mail alias or address.

It is up to you how you use the virtmaps feature to provide e-mail for your Virtual Subhost customers. Many Virtual Private Server administrators provide their Virtual Subhost customers with one e-mail User Account. Then they create virtmaps (often including a catch-all virtmap as well) for the customer that map to this single POP/IMAP account.

Creating Virtmaps
There are several methods you can use to create virtmaps on your Virtual Private Server.

NOTE: In order for a Virtual Private Server to recieve e-mail for a particular domain name, that domain name must appear on the "Cw" line in the Virtual Private Server ~/etc/sendmail.cf file. If you ordered a domain name from us (in other words, the domain is being resolved by our name servers) then we probably added it to your Virtual Private Server ~/etc/sendmail.cf file for you.

iManager
iManager Tools and Wizards allow you to use your own web browser to easily create virtmaps on your Virtual Private Server.
Telnet/SSH
You can create a virtmaps during a Telnet/SSH session with your Virtual Private Server. Connect to your Virtual Private Server via Telnet or SSH and do the following.
1. Add the virtmap to your ~/etc/virtmaps file. Use an online file editor, like pico, or transfer the file to your PC in order to add the virtmap. Be sure to download and upload the ~/etc/virtmaps file in ASCII mode.
  
  The virtmap you create in your ~/etc/virtmaps file should look something like this:
```
 
webmaster@subhost1.com   e-mail_address1 
webmaster@subhost2.com   e-mail_address2 
subhost2.com             e-mail_address3 
user@subhost1.com	 e-mail@remote-host.com
        
```
  The left hand side of the virtmap is the incoming e-mail address. The right hand side is the outgoing e-mail address, which can either be a local address or a remote address. If the left hand side is only a domain name then all e-mail sent to that domain name will be delivered to the e-mail address on the right hand side. All e-mail is delivered to the first virtmap that matches, if there is a virtmap that matches.
2. Run the vnewvirtmaps command.
  
  % vnewvirtmaps

Removing Virtmaps
iManager contains a utility to remove e-mail virtmaps. If you wish to use Telnet/SSH, connect to your Virtual Private Server via Telnet or SSH and do the following.

Remove the virtmap from your ~/etc/virtmaps file. Use an online file editor, like pico, or transfer the file to your PC in order to remove the virtmap. Be sure to download and upload the ~/etc/virtmaps file in ASCII mode.
Run the vnewvirtmaps command.

% vnewvirtmaps