I have a web server serving pages from a local IP address.
It is behind NAT which has correctly set port forwarding for 80 and 443 (tested by pointing to another local web server).
When trying to access from public address I get 403 while at the same time everything is reachable from local network.
Web server is apache.
What would be the order of things to check?
EDIT: Thanks everyone for their answers. Problem is resolved.
I checked apache access log (403 gets mentioned there), but that gave me no real clue. At that moment I was basically wondering if it is apache or the webapp (drupal) that is giving this response. After triple checking the apache config I also checked the webapp more thoroughly and found that non-local IPs were banned.
EDIT 2: If someone provides a good answer (or expand the existing) on what would have been a proper way to determine if it was apache or webapp I will accept it as an answer.