Oracle Linux 6.1 : No Internet Connection.

Question

I am not able to connect to the Internet with Oracle Linux 6.1.First,I had Oracle Linux 6.0 installed and running normally with normal Internet connection.I did an upgrade(upgrade option of the installer) and I ended up with No Internet connection.I thought that could be a problem with the option upgrade so I did a complete fresh install and NO LUCK I faced the same problem.The hint that can lead to the resolution of the problem is: When I had Internet connection the Gnome widget "green spinning wheel" was automatically turned on and searching for connection when I turned on my home router(as with other Gnome distros),and now I turn on my home router and nothing moves the "foreground/background computers" Gnome network widget stays the same No Connection.When I MANUALLY click on that widget and choose "System eth0" the "green spinning wheel" widget searching for connection appears and "CONNECTS" but in fact it is misleading because I still have no connection,I tested with Firefox for example.When I do ifconfig everything seems normal : interface etho with IP address 192.168.1.64(typical in home routers) gateway 192.168.1.254 netmask 255.255.255.0 broadcast adress 192.168.1.255 etc.,I did ifdown eth0 and immediately ifup eth0 but NO LUCK,so is this a dhcp that came with 6.1 problem or other known bug? anything that I can test/do?
Thanks.

Answer 1

I prefer using such a router as a bridge - it enables different PCs on that router to make separate PPPoE connections. E.g. one can connect using an Internet ISP account and another can connect to a private corporate network.
To check whether the router makes a successful connection to the ISP, you should use the web browser sysadmin interface of the router. You can view the authentication details it needs to use, check the router logs and so on.
From a Linux perspective, I do not see anything specifically interfering with that. The two basic issues that comes to mind is a Linux firewall (denying you access via that router), or a broken routing table.
You can use the +iptables --list+ command to check whether there are firewall rules in place - or do a firewall shutdown using +/etc/init.d/iptables stop+.
The routing table can be checked with the route command.
You can also consider setting DHCP up on the router and using DHCP on your computers - that way the network interfaces on the client side is automatically configured and usually less can go wrong this way then having to manually (and correctly) configure the IP stack and interfaces on the client side.