How to configure port forwarding in gitlab?

I have configured gitlab so that I can only connect to it from a specific ip address. In gitlab.rb file I configured the url this way:

external_url ''

and also configured ufw:

[ 1] 2000   ALLOW IN

When I want to access gitlab by browser I have to type additionally port 2000, so I would like to port forwarding to 443. I can’t give access to port 443 only to a specific ip address in ufw because i configured mattermost in this same server and must be access from everywhere. I tried port forwarding with apache2 or ngnix but gitlab listens on port 80 and because of this apache2 and nginx are not working. I also tried find solution in file gitlab.rb

nginx['listen_port'] = 443
nginx['redirect_http_to_https_port'] = 80
nginx['redirect_http_to_https'] = false

Please give me a solution to this problem.