3.4. Arranging Services From Your ISP

3.4.1.Service List A
3.4.2.Service List B
3.4.3.Service List C
3.4.4.Service List D

In each of the previous sections on connectivity, we direct you to the appropriate list of services that should be ordered from your ISP.

3.4.1. Service List A

3.4.2. Service List B

Services to order from ISP:

Services From Dynamic DNS Service

3.4.3. Service List C

Your web and FTP servers are available to the external world only when your server is connected to the Internet. DNS address records for web and FTP servers only need to be published if it is likely that someone external to your site will need to connect to them for a particular reason.

3.4.4. Service List D

Please read the important notes (below) on the limitations of this configuration.

important.gif Important

Some Notes on Service List D (Multidrop Mail)

Service list D is applied to configurations where the publication of DNS records is not practical either because your IP address changes frequently or because it is non-routable. Because there is no published address receiving incoming network connections, this configuration does not allow you to host a web page or FTP site using your SME Server.

In this case, e-mail is handled using a method called "multidrop", which involves temporarily storing all e-mail messages addressed to your domain in a POP mailbox at your ISP until your server connects and fetches them. Your POP mailbox must be large enough to hold the e-mail for your organization until it is fetched. If your primary ISP cannot supply this, you can use another ISP for your e-mail hosting.

As e-mail messages are delivered into the POP mailbox at your ISP, some of the addressee information is removed. To determine to whom the e-mail message is addressed, your server uses several heuristics. This works very well for normal person-to-person e-mail. However, messages from mailing lists (and other sources where the user's account name is not present in the headers) cannot be delivered. Any e-mail that cannot be delivered will be returned to the sender. If the e-mail cannot be returned to sender, it will be directed to the system administrator.

Some ISPs add a header to each e-mail message as it enters the POP mailbox to assist in determining the addressee. One common header tag is: "X-Delivered-To". If your ISP does this, make note of the header tag used so that you can configure your server to look for it (explained in a later section).

Because of the potential problems involved with delivery of e-mail to multidrop mailboxes, we strongly encourage you to consider other means of mail delivery before resorting to using multidrop.

Terms used in ordering connectivity and services


ADSL is a type of high-speed Internet access that uses regular phone lines and is available in many metropolitan areas.

Domain Name

This refers to theunique name attached to your organization on the Internet. For example, "tofu-dog.com" or "e-smith.com". If you don't have a domain name, your ISP can help you select one, ensure it is available, and register it.

DNS (Domain Name Service)

DNS, or Domain Name Service, refers to the software and protocols involved in translating domain names to IP addresses. Your server provides DNS lookup services for your local network, and your ISP typically also provides you with the IP addresses of DNS servers. These servers do not need to be configured into your server as the DNS server that is provided with your server will correctly resolve all local and Internet names.

DNS: Publication of DNS Address Records

The publication of DNS address information allows other DNS servers to look up your domain information. Your ISP must publish DNS address records associating the name of your web server ("www.domain.xxx"), FTP server ("ftp.domain.xxx") and e-mail server ("mail.domain.xxx") with the IP address of your server.

DNS: Publication of DNS Mail (MX) Records

The publication of DNS mail (MX) records is the method used to inform Domain Name Services worldwide that all e-mail to your domain ("yourdomain.xxx") should be delivered to your e-mail server ("mail.yourdomain.xxx").


ETRN is a command used for dialup solutions in order to retrieve e-mail temporarily stored at your ISP

Gateway IP Address

A gateway is the device on your network that forwards packets to and from the Internet. The gateway IP address is the IP address for that device.

Internet News Service

If you want access to Internet newsgroups, your ISP will need to provide the IP address of an Internet news server. The ISP will provide direction in configuring your web browser or other newsreading software.


PPP refers to the "Point-to-Point Protocol" used when a modem connects to the ISP.


"PPP over Ethernet" is a modified version of PPP that is used over some high-speed ADSL connections to the ISP.

Secondary Mail Server

A secondary mail server receives e-mail for your domain if your server is unavailable, and reattempts delivery later.

Subnet Mask (or netmask)

A subnet mask (or a netmask) has four numeric segments (each between 0 and 255) and looks like an IP address. It enables your computers to deduce what network they are on. Your ISP provides the netmask for the external network between the ISP and your server.