Ethernet adapter problem

[relativ]

Hello Everybody.

Problem: my raspberry cannot connect to the internet.

I have connected my pi with the right cable to my router and a good power supply.
I can access the Router page but not the internet.

Strange effect when i connect the ethernet cable to my pi the connection of all other clients is rejected.

Can somebody give me a hint or some tool/command, which allow me to catch the error?

Thanks a lot

[Zeek20]

Are all of your LEDs on beside the red light? Do you get anything for eth0 if you do "ifconfig" in the console?

[abishur]

Have you set up a static IP or is this the default behavior without editing your IP information?