How to change port for nginx?

Question

Nginx

Hello!
How to change port in nginx in bulk? Now port 81 is used.
There are about 30-40 sites on this bundle, is it possible to change the port without any problems? And which is better to change?
On apache2 port 80 is used.
Thanks

Answer 1

Why change the port?
Just close it from the outside if it is open.
In general, it is strange that Apache2 is looking into the world, and not Nginx. Why such a strange configuration?