How to Connect to a Consumer VPN on T-Mobile Home Internet (5G Nokia Gateway)

OKtw wrote:

I'm trying to setup Mozilla VPN WireGuard, but it's very slow on my new T-mobile Nokia 5G grey tube router I just setup.  Speed tests at around 3Mbps on VPN on the nearest servers to me, vs a great +90Mbps with VPN off while on T-mobile.  Prior to T-mobile, the Moz VPN used to run about 20Mbps on Cox on the same VPN servers.  The only settings Moz VPN has is Ipv6 off or on which makes little or no difference.  ¿Tienes alguna idea?

Here is what you need to do to restore your great speed with VPN for Windows 10 after you launch the Mozilla VPN WireGuard:​​​​​​​

1. Type this command line with admin authorization to display the interface:  netsh interface ipv4 show subinterface
2. You should see the MTU size & Interface name; then type this command line with admin to replace the MTU size of the VPN interface that you see with size,1376:  netsh interface ipv4 set subinterface "?" mtu=1376 store=persistent.  On this command, replace ? with the VPN interface that you see. For example, your VPN interface is wg-mozilla, then the comand should be:  netsh interface ipv4 set subinterface "wg-mozilla" mtu=1376 store=persistent
3. Repeat step 1 again to display the interface info and verify that the MTU size is 1376 for VPN interface; then run speed test again.  This should fix your probllem.

The following links which will described more about MTU size to fix this problem if you interest:

https://homenetworkgeek.com/mtu-size/

https://amithkumarg.medium.com/resolved-t-mobile-home-internet-vpn-issue-2f5ca594c23e