I tried several different Linux distributions (Gentoo, Debian, OpenSuse…) on my laptop, but every distribution suffered from the same problem – the maximal LAN throughput was around 5-7 kb/s… The laptop use a Realtek LAN NIC:
Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
I’m using the 8139too Kernel module for the LAN card. To fix the speed issue, I had to change some sysctl variables:
michu@opensusi:~/_down> cat /etc/sysctl.conf
net.ipv4.tcp_window_scaling = 0
net.ipv4.tcp_timestamps = 0
Activate the changes with “sysctl -p” and you’re done.