I'm doing an internship in a very little company and I need to configure the network. They have a Cisco router. I couldn't find the logs to login so I called their internet provider. Apparently they configured the Cisco router and doesn't allow customers to configure it. Only them can configure the router when asked.
I need to setup a server that will be accessed from the internet so I asked them about port forwarding (in a first time, before implementing some kind of DMZ later). I know that port forwarding is pretty insecure but temporally, I asked them to forward some port to my server. They accepted all my request, except for port 80 as they told me it was really insecure. Why would forwarding port 80 be more insecure than the others ports?