I use a DSL Connection since 4 years on Windows and 1 year on Linux. Since recent, when I connect, it connects perfectly. But when I open an Internet application (Firefox, Thunderbird, Evolution .........) the dialog boxes show "Connection Refused" at the end.
What could be the problem? Has my ISP disabled Linux?
Have you recently installed a firewall? Enable outgoing 67-68, 53, 80, 443 for web services.
Is your proxy broken?
Does your machine ping? "$ ping google.com"
No firewall, and I'm posting from Linx now. Its fine. Probably the Linux server was down temporarily on the ISP.