I'm currently running Debian 8 and I'm trying to force applications like Google Chrome to use IPv4 over IPv6 only for certain sites. My ISP natively offers IPv6 and it's amazing on all websites that support it except for Facebook. If I browse Facebook when I'm using an IPv6 connection the site is really slow and if I completely disable IPv6 everything start working again. So my aim is to automatically force an IPv4 connection only for Facebook and to keep it default for every other IP/domain. I tried to look online and the only method that I've found is to edit gai.conf but I'm unable to make it work. It seems that the file is being ignored. This is what I've added:
label 0:0:0:0:0:FFFF:ADFC:7806/128 5
precedence 0:0:0:0:0:FFFF:ADFC:7806/128 100
I converted the original IPv4 (188.8.131.52) to an IPv6 address and used that in the configuration file. Except for the two lines that I've added the rest of the file was commented. Can someone help me?