Mobile Internet in Europe. Which ports are usually closed?

Question

mobile connection

Hello.
A trip to Europe (Italy, Spain, France) is planned, access to a computer located in Russia via VPN will be required (there is a static IP address on the computer). Tell me, please, do major cellular operators in Europe (Orange, Vodafon) block any tcp \ udp ports or will it be possible to connect to a home computer via OpenVPN and L2TP + IPsec without any problems? And how likely is it that a European mobile operator is blocking access to Rostelecom's IP addresses?
Thanks for any help.

Answer 1

Previously, large European operators blocked voice communications in messengers. Perhaps now something has changed. You need to look for information on a specific operator and country.

Answer 2

The probability of blocking Rostelecom addresses is zero, it is only Rostelecom itself that blocks everyone.