Apps cannot connect to server - Yosemite

Hello,

I have a mac mini (mid 2011) and ever since I upgraded to Yosemite it's been nothing but trouble. I've been experiencing connectivity problems with Mail, Skype, and some other apps that would just flat out crash on me. So I found some joy in finding a new upgrade in the app store. But that made things worse. After the 10.10.2 upgrade, a reinstall, and a combo upgrade of the system, my connectivity problems have gotten worse.

Currently I'm able to surf with Safari and receive my Mail without any problem but that's about it. The App store cannot connect, Google Chrome cannot connect and basically all of my applications that need to reach a server for updates (e.g. Avast Antivirus) are unable to connect. When I try to ping, dig, telnet or nslookup a domain, it gets a connection time out. I've tried the following:

- Load/unload discoveryd

- Flush the cache

- Reset the router

- Check the certificates in Keychain

- delete networkinterface.plist

- Doing a reinstall

- adding a guest account and check whether there's a connection over there

- Do a wireless diagnostics. It tells me I have problems with WAN connectivity. (report can be found here: https://db.tt/tWX3DVDq)

Are there any other things I could try?