In my other question, I was trying to set up my mac as a server, and the thing they suggested after is setting it to a static local ip outside of the DHCP range so I could port forward to that and it would never change.
I know how to see/change the DHCP range through the airport utility. How do I go choosing the ip address and making it static? The Airport Extreme already always tries to give the same IP Addresses, but they recommended that I do this anyway as it is possible that it could change, with multiple devices connected.
Do I need to do it through the Airport utility? Or through system preferences? In the network section of system preferences, clicking on advanced, and under the TCP/IP tab "Configure IPv4", "Using DHCP" is selected. There is also a selected for "Using DHCP with manual address", which on selected makes "Renew DHCP Lease" button disappear, and make's the IPv4 address editable. Is this what I'm looking for? Thanks.
I'm also going to be using a DynDns account and the client application for a free domain name and to keep the global ip updated.
I think I figured it out -- My router's IP is 10.0.1.1. It's DHCP range is 10.0.1.2-10.0.1.200. "Using DHCP with manual address" keeps the router, dns, etc settings all the same, but it just lets you pick your own ip. So I set it to 10.0.1.201, just outside the range. And when I reboot its still always 10.0.1.201. So as far as I can tell it will do what I want, allow me to forward port 80 to my mac's IP without having to update when the mac's local IP changes. Now I realize why by default when I made the port map for "personal web sharing" it selected IP 10.0.1.201, because its the first outside of the range. Is this good?
EDIT: I followed Benjamin Schollnick's instructions instead.