Potential TTL leak? (when router and VPN are on same device)

I had been using GL-INet Puli with T-mobile, TTL modded. i also use the Puli device as VPN client to connect to VPN servers hosted at my house.

Lately, when I turn on VPN on Puli, speed reduces to 500 KB/s. Somehow, when using Puli in VPN client mode, it gets throttled by T-mobile. Without VPN, it reports TTL of 65 and works fine. With VPN on, it reports TTL of 58. Is this a recent bug in Puli/Mudi? TTL override doesn’t seem to apply to VPN traffic.

Any Ideas?

If the puli device is connected to the vpn server as a vpn client, then the speed will also be affected by the vpn server because the data to access the external network will be sent to the vpn server.

Since the data is sent to the vpn server, the routing is different between using vpn and turning off vpn, and the TTL may be different

The description here is not accurate, it should be connected to the vpn server when it will do so

Is there a way to set TTL to 65 when using VPN.

Do you mean to set the TTL of the SIM card? If so, you can set it via Manual Setup->Use Other Settings.

Are the two TTL values obtained by pinging the same address?

Correct. I don’t think TTL settings are working reliably when VPN is used on Puli (I’m assuming Mudi is the same). When I use 2 device setup eg phone/hotspot + router (beryl) it works perfectly. On Puli, there’s TTL leak somewhere and carrier throttles speed to 200 kb/s - 500kb/s.

Please let me know if you want me to send you some logs or anything to troubleshoot this. I’d really like to use 1 device for 4g LTE + router when carrying arround.