Howto: Tweak your Internet connection and maximize your bandwidth in Ubuntu/Linux via sysctl!

Here I will unleash a few hidden settings that should improve your internet speed, and work with all current linux operating systems including Ubuntu:
first open a Terminal via Applications->Accessories->Terminal
sudo gedit /etc/sysctl.conf
Then Paste the Following at the end of the file:
# increase TCP max buffer size setable using setsockopt()
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
# increase Linux autotuning TCP buffer limits
# min, default, and max number of bytes to use
# set max to at least 4MB, or higher if you use very high BDP paths
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216
# don't cache ssthresh from previous connection
net.ipv4.tcp_no_metrics_save = 1
net.ipv4.tcp_moderate_rcvbuf = 1
# recommended to increase this for 1000 BT or higher
net.core.netdev_max_backlog = 2500
# for 10 GigE, use this, uncomment below
# net.core.netdev_max_backlog = 30000 
# Turn off timestamps if you're on a gigabit or very busy network
# Having it off is one less thing the IP stack needs to work on
#net.ipv4.tcp_timestamps = 0
# disable tcp selective acknowledgements.
net.ipv4.tcp_sack = 0
#enable window scaling
net.ipv4.tcp_window_scaling = 1

Press Ctrl-S To save then alt-F4 to exit and then type:
sudo sysctl -p
to apply the settings.

Hitup a speed test site or a very healthy torrent and see how your speed is:
Test your Internet connection speed at Speedtest.net
You can disable all these settings by removing these lines you added via:
sudo gedit /etc/sysctl.conf