I have noticed this for awhile but recently, it seems to happen more often. When accessing web sites wth Ubuntu on my ISPConfg server, pages will not load, using Firefox. Out of the blue, it will just start working again. When trying to see the website with other computers(Mac, Windows, Pad), using Firefox, the websites load just fine. I dd notice that for my login page for ISPConfg, use a IP, not a domain. When using Ubuntu/Firefox, this page loads just fine. So, it seems to be having an issue with the domain resolution when sending web pages to my Ubuntu/Firefox computers. Any ideas? Thanks Joseph
Change the DNS to something better than what your provider offers. I would suggest google's DNS servers unless you use Comcast, they tend to be a bit persnickety at times.