A. The answer to your question depends on how the ISP has determined that your customer is sending UCE. Suppose your customer has configured Exchange Server to send all outgoing mail through the ISP's mail server. (This configuration setting resides on Exchange Server's Internet Mail Service Properties page, which Figure 1 shows.) In this case, the ISP is making a determination based on what it sees in its mail server logs. Your customer needs to configure Exchange Server to deliver mail directly rather than forward all mail to the ISP's mail server. Simply change the Message Delivery option setting back to the default setting of Use domain name system (DNS). In this configuration, outgoing mail will pass directly from your customer to the intended recipients, without involving the ISP.
Another possibility exists—the ISP's grumblings might be the result of complaints from your customer's email recipients. If an email recipient believes that a company is sending UCE, determining that company's mail-server IP address, domain name, and hosting ISP (based on the IP address or domain name) is a fairly simple matter. (Tools such as Nslookup and Whois, anti-UCE utilities, and Web sites such as Sam Spade—http://www .samspade.org—come to mind.) Lodging a complaint about a suspected UCE perpetrator with the company's ISP—rather than with the company itself—is a common practice. Most people believe that contacting the ISP is the most effective solution because many companies that spew UCE are indifferent to their victims' complaints. Most ISPs, however, impose anti-UCE regulations on their customers. Sufficient complaints to the ISP might cause the ISP to terminate services to the offending company.
Your customer needs to contact its ISP to find out whether recipients of its legitimate email are complaining about UCE. If your customer doesn't answer any such complaints, it might land on a "black hole" domain list. Then, ISPs that subscribe to the domain list might stop delivering your customer's legitimate email messages that attempt to pass through the ISPs' mail servers.
Figure 1: The Internet Mail Services Properties page