Setting up a Dial-up Internet Connection

---

You can create a dial-up Internet connection from IMail Server to your Internet Service Provider (ISP), allowing you to receive mail from an account with your ISP.

IMail Server does not perform dial-up functions or spawn off dialing commands. To start your RAS/PPP connection to your ISP, you need to either use a scheduling program or manually start the connection.

IMail Server uses the TCP/IP transport on Windows NT/2000; it does not configure the Windows NT/2000 TCP/IP transport. If you need to set up a RAS/PPP connection, refer to your Windows NT/2000 Help.

Receiving Mail from an Internet Service Provider

IMail Server is designed to work on a 7-day, 24-hour Internet connection, but you can also set up IMail Server to support dial-up connections.

When using a dial-up connection, your inbound mail from the Internet has to be stored somewhere on the Internet, usually with your ISP. Your ISP can store your mail in several ways. Three of the more popular ways that ISPs store mail for users are:

• Method 1: The ISP sets up individual mail accounts on the ISP computers. This method usually makes use of the POP3 mail protocol to read or retrieve mail - each user dials up the ISP and either reads or downloads their mail.
• Method 2: The ISP sets up individual mail accounts on the ISP computers, but the ISP forwards all the mail for your users to your mail server when your dial-up connection is up. This method uses the ISP's Internet domain name.
• Method 3: You have a registered Internet domain of your own, and you register your domain to point to the ISP computer. Your ISP stores your incoming mail and forwards it to your mail server when your dial-up connection is up.

To register your own domain, contact your ISP. In most cases, they will do the work for you. All you have to do is come up with a name.

If you use Method 1, then to use IMail Server, you will have to change to either Method 2 or 3 to receive mail from your ISP. IMail Server cannot log into individual mail accounts on your ISP mail server, retrieve the mail and then parse the mail correctly. An Internet standard for this does not exist.

Setting Up the Server for Dial-up Access

Setting up IMail Server using a dial-up connection is the same for both methods 2 and 3 above. Use the following procedure to set up your IMail Server computer:

1. Create mail accounts for users on the IMail Server computer. For more information, see "Working with User Mail Accounts"..

   If you use Method 2, the users' names need to be the same on both the ISP's computer and your IMail Server computer.

2. Tell Windows NT/2000 about your e-mail domain name.

   When Windows NT/2000 looks up a domain name, it first searches the \winnt\system32\drivers\hosts file. If there is no match, Windows NT/2000 asks a Domain Name Server (DNS) for the IP address for the domain name.

   This creates a problem, as your Windows NT/2000 computer has a different IP address than your ISP's computer. When IMail Server looks at the incoming mail, it looks up the domain name to which the e-mail is addressed. If the domain name points to your ISP's computer (your ISP's IP address), then IMail Server will send the mail back to your ISP's computer (which it thinks is correct). Mail will be bounced back and forth until one of the computers sends the mail message back to the original sender.

   To avoid this problem, set up the domain as a virtual host, then add the domain name to which your incoming mail is addressed (either your ISP's if Method 2, or your own if Method 3) to the Aliases text box in the Virtual Host Configuration dialog box, and make this domain name point to the IMail Server computer's IP address.

   For example, if you are using Method 2, and the computers involved have the following addresses and names:

   ISP's IP address:	156.21.50.1
   ISP's domain name:	isp_are_us.com
   IMail Server IP address:	156.21.50.240
   IMail Server Name:	my_imail_machine 
   

You would make the following entries in the \winnt\system32\drivers\hosts file:

156.21.50.240	my_imail_machine 
156.21.50.240	isp_domain_name.com 


   You can have multiple names pointing to the same IP address. This also helps if your computer is receiving mail for multiple domains. Just place each domain name in the hosts file pointing to the IMail Server computer's IP address.




   If you are using Method 3, and the computers involved have the following addresses and names:




   ISP's IP address:	156.21.50.1
Your Domain Name:	my_domain_name.com
IP address for  
       my_domain_name.com:	156.21.50.1
IMail Server Name:	my_imail_machine
IMail Server IP address:	156.21.50.240




   ...you would make the following entries in the \winnt\system32\drivers\hosts file:


156.21.50.240	my_imail_machine 
156.21.50.240	my_domain_name.com 

3. Unless you plan on maintaining a 24-hour/7-day dial-up Internet connection, you need to have your ISP spool all the mail for your company. Then, have your ISP set up their computer to try periodically sending mail to the IMail Server computer.

   How often the ISP attempts to send mail to your server depends on how often your dial-up connection is up. Consider the following factors in determining queue times. The first factor is the most important.

   • How long will your dial-up connection last (10, 20, 30 minutes)?
   • How often will your ISP's computer try to send the spooled mail to your NT computer?
   • How often will your NT/2000 computer try to send mail to the Internet?
   • How much mail will you receive and send when you make your dial-up connection?

     For example, if the connection time will be 20 minutes, and you will have relatively light traffic (50 received and 50 sent) and relatively short messages (no attachments, or large files), you could set up the queue times as follows:

     Connection Time:			20
     ISP Queue Time:			15
     IMail Server Queue Time:			15
     E-mail Quantity:			50 received/50 sent (short messages) 
     
     
        In this example, the Connection Time is the amount of time your IMail Server is connected to the ISP's computer (this would be set in your scheduling program). The ISP Queue Time determines how often the ISP mail computer tries to send mail to the IMail Server. The IMail Queue Time determines how often IMail Server tries to send mail to the ISP or Internet (this is set on the SMTP tab). 
     
     
     
     
        To be sure your mail gets processed regardless of the connection time, make the queue times less than the connection time. If you expect to receive or send greater numbers of messages, or more lengthy mail than in the example, you can either increase the connection time, or decrease both queue times.
     
     
     
     
        Alternatively, you can use the ETRN command to manually retrieve mail from the ISP's mail server. See "Using ETRN to Retrieve Mail".
     
     
     

Remember that IMail Server does not do scheduling. You need to obtain a scheduler to have the connection automatically dial, connect, and disconnect.

Ipswitch, Inc. http://www.ipswitch.com

©Ipswitch 2001