Internet is working fine but local trafic goes really slow, sometimes to slow to download 70kB with ftp of via samba. How to chceck what is the problem? Under windows everything works fine. Thanks for help.
Pings are allover LAN are fine but slow (+ - 0.305 ms)
The only fast working is sftp.

I don't know where to start solving this problem.

Thanks for help.