Edit: So apparently these are not really IP-addresses but rather hostnames.
I tried out the netstat to find any suspectful connections and then I found quite some remote-addresses that were really weird to me, for example the following:
ec2-3-235-82-211:https
fra24s07-in-x0a:https
g2a02-26f0-0300-0000-0000-0000-5c7a-f589:https
wm-in-xbd:https
and156:https
I was wondering what any of these mean and also what the in means at 2. and 4.?