I cannot find any answers for this, so if anyone here can point me in the right direction...
Edited for clarity
Ubuntu 18.04 with low latency kernel.
I get horrible download speeds at times, especially with Steam, but also other streaming sites. I have found that if I manually disable ipv6, I get advertised download / upload speeds on my isp connection. If it is not disabled, things become really slow in a short period of time (like 2 Kbps). When I use my vpn service, everything runs fast because it disables the ipv6 stack, then re-enables it upon closing the vpn connection.
However, I got tired of having to manually disable when not using the vpn, so I permanently disabled ipv6 via grub. This completely disabled my vpn service. Even their support staff were unable to help. So I changed everything back to the way it was.
I have since disabled ipv6 in my router, which has helped increase overall speed when the network stack is at default (ipv6 enabled). Having both the router and Ubuntu ipv6 disabled increases my speed by several Mbps up and down.
To recap - ipv6, when enabled by default, slows down my Internet connection, but disabling it and only having ipv4 running makes everything faster. Disabling ipv6 in both the router and the OS makes things Speedy Gonzales. Disabling ipv6 permanently via grub kills vpn access.
Is there a way to permanently disable ipv6 so it does not break my vpn? Or some type of desktop script that can disable it manually with a click?
Thanks in advance!
How I disable ipv6 manually (checked with ip a):
sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1 sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
How I permanently disabled ipv6:
FROM: GRUB_CMDLINE_LINUX_DEFAULT="" GRUB_CMDLINE_LINUX="" TO: GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1" GRUB_CMDLINE_LINUX="ipv6.disable=1"