During the installation of exchangelib the installation tries to connect to the internet to get dependencies.
On this computer it is not possible to to open the firewalls to provide the access - it is a very restricted system.
Is there a way for an offline installation of the exchangelib?
Best Regards 
Klaus Heubisch
You have a couple of different possibilities. I think the most simple one is to create a virtualenv on a system that does have Internet access and install exchangelib and its dependencies there. You can then copy that virtualenv to the system with no Internet access.
Virtualenvs contain absolute paths, so you would need to either copy it to the same path on the other server, or make the virtualenv relocatable.
I cannot install exchangelib on a very restricted system which has no internet connection and it is not possible to create one