I use microsoft.xmlhttp at my server (NT IIS 4.0) to get data from another server (IBM iSeries) and found that every response to my page is still same as the first response I received. But when I change my server to windows 2000 with IIS 5.0 I found no problem. <BR>I also used following code for both environment. but it not help.<BR>Response.Expires = 0<BR>Response.Expiresabsolute = Now() - 1<BR>Response.AddHeader "pragma","no-cache"<BR>Response.AddHeader "cache-control","private"<BR>Response.Buffer = False<BR>Response.CacheControl = "No-cache"<BR>Moreover if I still use IIS 4.0 but change request URL by adding some characters to the end of URL in order to make it as new request, the response I got look OK. It looks like cache problem or IIS property problem. Can you help me?