T-Mobile doesn’t support IPv4

It probably has to do with being native ipv6 and needing to ride a 6to4 nat to reach the broader internet.

Start at 1400 and walk the MTU down by ~50 until you find stability, then id creep it back up by 10 to find the ‘perfect’ size, but that part isn’t really needed if you’re impatient. :)

E. I found 1290 was needed for reliable VPN over an ATT nighthawk hotspot.

I’ve had intermittent issues with T-Mobile on hotspot too. I’m not sure how helpful this will be but here’s my 2 cents. The only params I played with that seemed to help were the :

1- MTU (if I remember correctly, I had to dial it down to 1300)

2- and using IPv6 instead of v4.

This will depend on the APN you’re using for T-Mobile. I believe they have a legacy one that only uses IPv4 whereas their new one supports IPv6 only (I wasn’t able to find clear info about this but this is my guess). In any case, I have my wireguard server setup to support and use both IP versions and when v4 doesn’t work for me, switching to v6 fixes the issue for a while. At some point I even suspected they were heavily throttling wireguard traffic, which may be the case but who knows.

I hope this helps, good luck!

How is your speed and connection quality otherwise? The fact that your work VPN doesn’t stay connected – I’m assuming the client is running on your PC – is odd. That makes me think there may be some issues with signal strength or tower congestion. TMobile also gives home internet a lower priority than cell phone traffic.

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:

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