Ubuntu – can’t access internet via ethernet, but i can via WiFi

ethernetinternetlannetworkingwireless

what happens is my laptop connects to the router via lan cable but I can't access internet. while on my other laptop I can.

Thought it was a lan cable issue, so replaced it. Still the same problem and as my other laptop connects to the same router via the same lan cable there has to some problem with my laptop.

So tried changing the router but keeping the lan cable same, and I can connect to the router and access Internet as well!

So somehow I can't access internet on my laptop connected to my router via lan cable! Anyway WiFi works just fine.

Using Ubuntu 15.04 right now.

output of lspci -knn | grep Eth -A2

01:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller [10ec:8136] (rev 05)
Subsystem: Dell Device [1028:0597]
Kernel driver in use: r8169

Best Answer

You need to disable wireless network when you connect by Ethernet.

Any OS and Ubuntu has a routing table where rules are set up where to send packets in order to reach Internet or specific network segments.

If your wireless network is enabled, default route is set up to wireless interface and you can't get access to Internet.

General rule is that you can't use more than one network interface in a system without setting up routing.

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