Given root access to a server that someone else had set up (and they either have no knowledge of how it's configured or won't tell you), what would be the fastest way to determine:
1) What webserver is running at port 80?
2) Is there any special configuration such as a reverse proxy that I need to be aware of?
3) Can the server be administered manually or must I use CPanel/Webmin/etc?
4) Is the server handling DNS or must it be setup elsewhere?
There are also many application specific questions such as should Ruby and gems be installed system-wide or use RVM to manage gems and rubies?
I don't want to mess up any existing services on this server but it's very difficult without being given any information by the previous admin.