Unsolicited Commercial Email (UCE), also known as Spam, is a growing problem for companies and individual with an internet presence. While legitimate mailing lists of interested customers are useful to a business, a constantly increasing volume of Email messages, often advertising semi-legal or questionable products, are being delivered to thousands of Email addresses.

While the legal definition of UCE varries from one place to another, spam.abuse.net provides a general description on their What Is Spam? page. The following is an excerpt from that page:

Spam is flooding the Internet with many copies of the same message, in an attempt to force the message on people who would not otherwise choose to receive it. Most spam is commercial advertising, often for dubious products, get-rich-quick schemes, or quasi-legal services. Spam costs the sender very little to send -- most of the costs are paid for by the recipient or the carriers rather than by the sender.

In addition to consuming your Virtual Private Server resources, spam can create a load on the network infrastructure that allows your VPS to be accessed by others. For these and other reasons, the ITS Acceptable Usage Policy specifically bans sending spam:

Subscribers violate ITS policy and their service agreement when they, their customers, affiliates, or subsidiaries engage in ... spamming. Sending unsolicited bulk and/or commercial messages over the Internet ... is not only harmful because of its negative impact on consumer attitudes toward ITS, but also because it can overload ITS's network and disrupt service to ITS subscribers. Also, maintaining an open SMTP relay is prohibited. When a complaint is received, ITS has the discretion to determine from all of the evidence whether the e-mail recipients were from an "opt-in" email list.

Preventing Spam Relays

Because of the growing anti-spam sentiment among internet service providers, spammers frequently try to use another person's E-mail server to send their messages. Your Virtual Private Server is designed to prevent your server from being used as a relay. SMTP authentication prevents anyone who doesn't have a legitimate E-mail account on your Virtual Private Server from sending E-mail from your server. We also provide NMS Formmail, which prevents spammers from using your Web-based forms to send spam.

Blocking Incoming Spam

NOTE: Any spam-filtering techniques you may use could also block legitimate E-mail messages. The spam blocking techniques described here are effective, but are not guaranteed to work. Some spam may still get through, and some legitimate E-mail may get blocked.

There are a number of different tools available to help keep unwanted spam out of your Virtual Private Server Email accounts.

DNS Block Lists

A DNS block list (or blacklist) looks up the IP address for incoming connections in a master list of known or suspected spam sources. We have created an installer to assist in configuring sendmail to use several popular block lists. To use a block list, run:

vinstall sendmail-rbls

You will be prompted for what block list(s) to install. We recommend, the default, the Spamhaus SBL+XBL.

More Information

For more information about spam and resources that can be used to fight it, see the following Web sites:

Please note: the information on this page applies to ITS web hosting plans. It may or may not apply to other environments. If you are looking for a feature described here, or better support from your hosting provider, please consider hosting your site with ITS!

1555 N Naperville/Wheaton Road, Suite 107
Naperville, IL 60563
phone 630.420.2550
fax 630.420.2771