<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
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--></style></head><body lang=EN-US><div class=WordSection1><p class=MsoNormal>Hello,</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m using the latest version of Firefox on my Windows 10 Home edition and Linux Ubuntu 14.04 LTS desktops. I noticed that Firefox always sends two DNS requests: A and AAAA requests. I did an experiment to see which API is used by Firefox and found that the API getaddrinfo() does send 2 DNS requests on my Linux machine while it sends only one A request on my Windows machine. This doesn’t guarantee that Firefox always uses this API. Does Firefox uses multiple APIs depending on the OS? I would like to know which API does Firefox use when sending DNS requests.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thank you for your help. This is part of my PhD research and I appreciate your cooperation. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sincerely,<br>Fatemah Alharbi<br>PhD Student<br>Computer Science Department<br>University of California, Riverside</p></div></body></html>