Ubuntu Server forgets how to connect using ethernet

Question

Assume I have a base class Shape, and a derived class from Shape, Triangle, defined in a project X in Visual Studio. I also have a class Transformations in a project Y in which I want to be able to call dynamically the appropriate method:

void Rotate(Shape& shape);
void Rotate(Triangle& triangle);

I'm trying to do this using a visitor pattern following this.

In both Shape.cpp and Triangle.cpp, I implemented to following method:

void rotate(Transformations trans) {
    trans.Rotate(this);
}

However, project X is compiled before project Y, and project Y depends on project X, which leaves me with circular dependencies.

Unfortunately, forward declaring the Transformations class is not enough, as the knowledge of its member functions is necessary.

The answers provided in this thread did not help in that regard.

Solution 1

3 things to check:

1. what eth device do you see? dmesg | grep eth will show you. was it renamed?

2. if eth0 is available, sudo ethtool eth0 to see if it is really up.

3. is the nic light on (most nics should have indicator lights)

Solution 2

probably to late, but take out auto eth0. It will auto config anyways when it boots. I had this problem for some time before reading about the fix.

Comments

[Michael]

Alright. 1. When I typed that in is filled the entire screen with entries and since I have lost SSH to the server I can only summarize. I see Numbers in brackets on the left then on each entry it says 'eth' in red, some sort of timestamp or something (all set to 0000:00:07.0) eth0: link up/down. It says up/down/up/down/up/down in sequence. 2. ethtool command not found. 3. Network indicator light is on both the router and the server.

[johnshen64]

looks like it may be a link problem, if it keeps going up and down. try dmesg | grep eth0 | tail -10 just to make sure it is indeed eth0. try to reseat your nic connectors to see if it does anything.

[Michael]

forcedeath eth0 link up/down/up/down I'll try reseating.

[Michael]

Alright just checked the nic connectors.. it is part of my motherboard so it could not be moved really.

[johnshen64]

just unplug nic cable and replug. also, you can replace the nic cable with a known good one to rule out that it is the cable. if this still does not fix it, then i would say your nic port is kaput. do you have another nic on the server or can insert a nic card to replace this nic? looks like it is a nic hw issue most likely (after ruling out cable issue that is).

[Michael]

Alright replaced cable and still encountering issues I'll try seeing if a new network card works.

[Dan]

Not too late for me, thanks! Any idea why the 'auto eth0' balls things up?