Recently, I downloaded BOINC 7.8.3 for Windows (10, x64) to test my own BOINC project also in that operating system. The project server is only accessible via IPv6.

In Linux (on the same machine, with the same IP address) everything works fine -- BOINC Client is able to connect to the project server, download work items and upload results.

However, in Windows I was not able to add the project to BOINC Manager, which kept complaining "HTTP error: Couldn't resolve host name" (in the event log) and that the project may be temporarily off-line, which was definitely not the case. After poking into the source code of BOINC for a while I compiled my own DLL of Curl 7.42.1 using Visual Studio 2017 and replaced the "libcurl.dll" bundled with BOINC by the newly compiled library. Suddenly, I was able to add the project and everything started to work as it should!

What could be the cause? Is Boinc's "libcurl.dll" compiled without support for IPv6? If so, why?