程序代码：

<%
dim ComeUrl,cUrl,AdminName

ComeUrl=lcase(trim(request.ServerVariables("HTTP_REFERER")))
if ComeUrl="" then
    response.write "<br><p align=center><font color='red'>对不起，为了系统安全，不允许直接输入地址访问本系统的后台管理页面。</font></p>"
    response.end
else
    cUrl=trim("http://" & Request.ServerVariables("SERVER_NAME"))
    if mid(ComeUrl,len(cUrl)+1,1)=":" then
        cUrl=cUrl & ":" & Request.ServerVariables("SERVER_PORT")
    end if
    cUrl=lcase(cUrl & request.ServerVariables("SCRIPT_NAME"))
    if lcase(left(ComeUrl,instrrev(ComeUrl,"/")))<>lcase(left(cUrl,instrrev(cUrl,"/"))) then
        response.write "<br><p align=center><font color='red'>对不起，为了系统安全，不允许从外部链接地址访问本系统的后台管理页面。</font></p>"
        response.end
    end if
end if

AdminName=replace(session("AdminName"),"'","")
if AdminName="" then
    call CloseConn()
    response.redirect "login.asp"
    response.End()
end if
sql="select UserName from Admin where UserName='" & session("AdminName") & "' and Password='" & session("AdminPassword") & "'"
set rs=conn.execute(sql)
if rs.eof and rs.bof then
  rs.close
  response.Redirect("login.asp")
  response.End()
end if
%>