All ISP's use DHCP. Using a Static Public address for remote access from outside your home network works great provided your IP Address doesn't change frequently. Your ISP controls your DHCP age timer and depending how they set it up, you may end up getting a new address each and every time your DSL/Cable modem resets or powers off.
You can type in this URL whatismyip.com to retrieve your Public ISP IP Address. The IANA has reserved theses addresses spaces for Private Networks and you WILL NEVER use or see these used on the Internet:
10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
The address you want to use is the address from what returned after you typed whatismyip.com. Note: again this address may or may not change. If it does, you will need to make the change in your APEX client on your handheld to reflect that address every time it changes. If it doesn't change like mine hasn't for over 4 years, then your golden.
The only way to get around this is to sign up for a DNS Service which maps your APEX name to your ISP Public Address space and then you can use a DNS or APEX name and TCP/UDP port you defined and you’ll never have to worry about using a IP Address again. This service typically runs $12-$15 a year and it's well worth it if your experiencing your IP Address changing all the time.
The one thing you will need to do is set up Port Forwarding. What this does is maps the Private address of your APEX such as 192.168.X.X to a TCP/UDP port. The default port is 80, but some ISP’s block inbound traffic for port 80 and you’ll need to define your own port. You can define any port/ports up to 65535. If you change the default port of port 80, please note that you will be required to go into your APEX unit and change the configuration to match the port you used in the Port Forwarding screen.
<span style="color: Blue">“Again port 80 is the default for your router and your APEX unit”</span>
For this example I’m illustrating using an example Public Address of 76.12.13.103 and a port 4600.
The IP Address and Port is an example only:
If you were to access your APEX from a browser outside your home network you would type in the following URL: http://76.12.13.103:4600">http://76.12.13.103:4600</a>.
In the APEX Client in the Host field you would use 76.12.13.103 in the Port field you would use 4600
The internet knows that that this IP Address belongs to your ISP and it will get routed to your home network. The 4600 is the TCP/UDP port you defined in your home router Port Forwarding Table for the APEX.
For this example I’m illustrating an example Private Address that’s configured in your APEX unit. This is what you would use while accessing the APEX from your browser from your home network
[B]The IP Address and Port is an example only:[/B]
[IMG]http://192.168.1.11:4600">http://192.168.1.11:4600</a>
So basically what I’m saying is your APEX client or Web Browser uses a DNS or Public address with TCP/UDP port from outside your home network and the Public IP address along with the TCP/UDP port gets sent to your home network and your home router such as a Linksys, Belkin or other looks at the port forwarding table and sends the request to the APEX IP Address with the port number you configured in the Port Forwarding Table.
Yup, It’s that simple. I hope this helps!!
Oh,I forgot to mention that if your using a DSL Modem, sometimes you have to setup some Port Forwarding in the DSL/Modem. I just did this for a neighbor friend of mine that's running DSL and I had do do some stuff in the cable modem to get his to work properly.