I have a MacBook Pro running on El Capitan (but the issue was already present before the upgrade, so it's not related). I have the Mac since a bit less than a year. It is still running perfectly but since a couple of weeks, the internet is really weird. It's constantly completely blocked and just not working. The wifi works well: on my iPhone it is never down, but every 30min or so, it just blocks while I am browsing (but the issue is there on all the apps used, from Xcode to my FTP client, and so on), and it doesn't work anymore. When I just turn the wifi off and on again, it works well for some time, and then the issue comes back again.
I tried changing the DNS (by using this software that indicates the fastest DNS to use) and I thought it worked at first, but the issues are back again.
I have tried deleting the wifi from my keychain and adding it again the problem is persisting.
Obviously I have restarted the modem a couple of times too, no difference.
Any advice?