When I open firefox there is a blank page, which is normal. However, when I analyse the network traffic with wireshark I notice there are automatic connections to several websites. Including reddit.com, twitter.com, facebook.com, youtube.com, wikipedia.org, example.org, ipv4only.arpa and also to some mozilla domains. Is this normal behavior or should I be worried ? Also, is there a way to disable this if this is normal behavior ?