Hi John,

Quotation from John at November 18, 2018 19:55:
> ... on port 53 ... do _not_ work when I connect via LTE
> (Verizon supplying the data).  On LTE, I am no longer able
> to transfer data to/from the server peer but I can handshake
> with it.

Vodafone blocks UDP traffic on port 53 in LTE.

> 1) What can I try on the server peer side to diagnose?

I would check with tcpdump. it seems Verizon does some package
inspection, maybe reducing MTU will do?

> 2) Do people feel that Verizon is actively blocking the
> connection on port 53?

Not with Verizon but Vodafone which does a complete block -
not even the handshake goes through. Not sure about the cause
for that, maybe they want to control your DNS that way.

Regards,
M. Dietrich