The only thing I can think of is that you may have a web application that tries to use the SNA servers to retrieve data. I can't be sure as it has been a couple of years since i used SNA in a production enviroment. Here is a link to the page on microsoft that discusses using SNA to connect to DB2 applications
microsoft SNA source

Microsoft Back Office components IIS, SNA Server and StarQuest's StarSQL connect a Web server to an IBM host for publishing dynamic data on a browser client.

The result is a Web server that can combine static web pages with dynamic data from the company's corporate DB2 database. For example, the Web page of an air freight company might get HTML pages from a local file and dynamic data from a remote DB2 database. This would allow a customer to enter an air bill number in a Web page to request up-to-the-second information on their package.

An IIS Web server has the ability to access relational databases using the Active Server Pages. The ASP uses ODBC drivers to access relational databases and can use StarSQL or other ODBC-to-DRDA drivers to access DB2. The Web server connects to the IBM host through SNA Server.

(See Appendix 3: Sample HTML and Active Server Page)
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hope you finid some information that helps here. I am assuming a connection through SNA to a DB2 database on an IBM machine like an AS400.