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Hi,
I try to force DNS prefetching of specific hostnames using IE9 and IE10. I added the following code to my HTML page in the head section:
<link rel="dns-prefetch" href="http://www.domain1.com">
<link rel="dns-prefetch" href="http://www.domain2.com">
<!--[if IE 9]>
<link rel="prefetch" href="http://www.domain1.com">
<link rel="prefetch" href="http:///www.domain2.com">
<![endif]-->
when looking at the webpagetest result I can see actually DNS prefetching for Firefox, Chrome and Safari but I can't see any DNS prefetching for IE9 or IE10.

Here is an another example from http://www.amazon.com The amazon site's source include the following code:
<meta http-equiv="x-dns-prefetch-control" content="on">
<link rel="dns-prefetch" href="http://g-ecx.images-amazon.com">
<link rel="dns-prefetch" href="http://z-ecx.images-amazon.com">
<link rel="dns-prefetch" href="http://ecx.images-amazon.com">
<link rel="dns-prefetch" href="http://completion.amazon.com">
<link rel="dns-prefetch" href="http://fls-na.amazon.com">

webpagetest.org results for Chrome: http://www.webpagetest.org/result/130414...2d2ac6b65/
webpagetest.org results for Firefox: http://www.webpagetest.org/result/130414...d8cccc1e3/
webpagetest.org results for IE10: http://www.webpagetest.org/result/130414...704990ba3/

In those results I can see a DNS prefetching in Chrome and Firefox but not in IE10.

When looking at the wireshark tool for those sites I can see DNS prefetching for both IE9 and IE10.
I would like to ask why can't I see the DNS prefeching in the webpagetest tool for IE9 and IE10.

Thanks.
Try turning on tcpdump on the webpagetest runs to see if you see it in those wireshark traces. When you are testing locally you are also running into the heuristic-based prefetching that the browsers do based on what they have learned about the sites from previous visits. WebPagetest wipes out all of the heuristic stores when it clears the caches (just clearing the caches on IE will not do it - the data is a royal pain to clear: http://blog.patrickmeenan.com/2012/11/cl...as-it.html )
I turn on tcpdump on the webpagetest runs and I saw DNS prefetching in chrome but not in IE10.
Do you know why it doesn't work in IE? Does IE support DNS prefetching? If so, is there any way I can see actually DNS prefetching in IE?
Saw your thread with mdsn/technet - I'm not sure what it takes to tickle IE 10 to do the DNS prefetch. Could be it only does it on idle with the expectation that it's for the next page - kind of like what the link prefesh was intended for.
We are also facing the same problem. We have well applied the pre-fetch tags on head element in our HTML but while trying to confirm using the webpagetest.org seems that IE is not working as supposed. Not sure if this is a client problem. Chrome and FireFox are working fine.

Chrome - OK: http://www.webpagetest.org/result/150701_SE_YMG/
Firefox - OK: http://www.webpagetest.org/result/150701_BT_YMP/
IE11 - NOK: http://www.webpagetest.org/result/150701_Z6_Y5V/

Could you please assist? Let me know if further clarification is needed.
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