I have a web-application that I'm testing the frontend performane using looks like YSlow and http://www.webpagetest.org/
One of the things I notice the most is that the time to perform the DNS lookup on my web-site is huge (hundreds of milliseconds).
However, if I use these tools to test Yahoo, Google, Microsoft, etc - the DNS lookup time is near 0.
Question: What might be causing my DNS lookup time to be so large?
I found that Yahoo states that DNS lookup is typically 20-120 ms; however, for my website - it's closer to 350 ms. Any ideas why my DNS lookup is so much longer that what Yahoo typically experiences?