I was on CenturyLink (basicly DSL) a couple of builds ago when I started having big problems connecting to any servers. I thought I'd tried everything and had pretty much given up. Then I got rid of CenturyLink and got Comcast Xfinity and updated to build 798 and I could connect again, not to every server but a lot of them. Well, I was setting up the cable modem/router and noticed it's firewall was set on "low" but didn't even really think about it because I was more worried about getting everything else going. After that and after running a few races in rFactor2 I was back in the modem/router settings looking around and set the firewall to the "medium" setting. A couple of days later I'm wanting to run a few laps....and can't connect to any servers, what the heck. Now I'm back in my firewall settings in my anti-virus, checking it again, making sure anything rFactor2 is being allowed, then I turned it off, still no connecting. Son-of-a-biscuit, here we go again. Of course I'm blaming rFactor2, what else could it be? So, I'm sitting here thinking today and it hits me. I have TWO firewalls running. And the only thing changed was moving to that "medium" setting in the router. Sure enough, I change it back to "low" and I'm racing again. Hopefully this might help anyone else having this type of problem.
you don't mention your router model? I don't have any AV,have router Firewall on and just use windows own Firewall. routers usually have a hardware firewall,which is better than a software one.