您的顶级域名需要支持多前缀解析，需要指向独立IP地址

<%Server_Name = Request.ServerVariables("SERVER_NAME")
For I=1 To Len(Server_Name)
If Mid(Server_Name,i,1)="." or Mid(Server_Name,i,1)="@" Then Exit For
USER = USER & Mid(Server_Name,i,1)
Next
set conn =Server.CreateObject("ADODB.Connection")
conn.open "driver={Microsoft Access Driver (*.mdb)};dbq="&Server.MapPath("wwwurldata.mdb")
Set rs = server.createobject("adodb.recordset")
sql="SELECT * FROM url WHERE username='"&user&"'"
rs.open sql,conn,1,2
if rs.eof or rs.bof then
%>
<meta http-equiv="refresh" content="0;url=<%=URL%>">
<%End If%>