Exceeding PPPOE Speed Limit with VPN
How to exceed the speed limit of your service provider on PPP conection ? You need the wrong username and password.
Sometimes we need high speeds when we uploading our projects from the server or downloading from the server. My service provider lowered the upload speed from 4 megabits to 2 megabits, this is a very bad situation for me.
I started researching to overcome this hurdle.
When I entered the PPPOE user name and password incorrectly, then I tried to send ICMP packages to Google, I got the warning “Packets were filtered” but I noticed there was no problem with the DNS query.
That is, all protocols and ports except UDP 53 are closed.
I installed OpenVPN on my server and changed the default port to 53 UDP. When I started the OpenVPN connection from the computer, I knew I could now internet access it without being caught in the speed limit. If the user name and password are incorrect in the pppoe server, the profile information can not be found on the system and access is granted without restriction.
After this system, other devices in the house did not have internet access, but the solution is simple.
Set up one mini-arm pc (like raspberry pi) as the default gateway and have the device connect with vpn. For example your server ip adress is 1.2.3.4 and add 1.2.3.4 via your router ip adress and connecting interface.
sudo ip route add 1.2.3.4 via 192.168.2.1 dev eth0
Change dhcp default gateway to raspberry pi ip adress on your router. 
Enable nat on your raspberry pi. İf you are using tap interface change tun0 to tap0.
sudo sysctl -w net.ipv4.ip_forward=1
sudo iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE #
Transfer openvpn connection file (*.ovpn) to raspberry pi and connect.
sudo openvpn your-openvpn-file.ovpn
Congratulations.
Now all your internet connection goes through the raspberry pi and you do not get in the speed limit.