I noticed that internet sites were loading slowly or not at all on some systems that I had upgraded from Windows XP to clean installs of Windows 7. Pinging internet sites was fine, nslookup and dig queries all returned correct DNS resolution with no errors.
Sites such as google would load okay but larger sites like Amazon would load halfway or simply not load at all. Keep in mind these symptoms were seen on clean installs of Windows 7, and because of that malware causing these problems was thrown out of the equation.
As stated earlier all attempts to ping outside hosts worked perfectly fine. All DNS resolution was working beautifully so to dig a little further I fired up Wireshark and noticed the following: