This topic provides a reference for setup of port forwarding, to connect from outside, with the Airport Extreme 1st generation Router.
Step 1: Connect to your Airport Extreme 1st generation Router with the Airport Utility.
Step 2: Click on "Manual Setup" at the bottom left corner of the utility.
Step 3: Write down the external IP address of your router. It should NOT start with "192" or "10".
NOTE: You may need to configure port forwarding through your Cable or DSL modem and any additional routers if the Airport Extreme does not have an external IP address that does not start with "192" or "10".
Step 4: Click on the "Internet" tab and "NAT" sub-tab, and then click on "Configure Port Mappings..."
Step 5: Next, click on the "+" symbol to add the port mappings.
Step 6: Enter in the 3 ports respectively that your Splashtop Remote streamer and client are set to use in the Public and Private TCP port fields. By default, these are 6783, 6784, and 6785.
Also, enter in the internal IP address of the Mac/PC that you want to connect with (refer to STATUS page of Streamer).
NOTE: This internal IP address of the Mac is dynamic. You may need to come here again to modify it, once your router changes your Mac's internal IP address.
Add these 3 ports one-by-one:
NOTE: For additional computers you want to connect with, repeat Steps 4-6, but remember that they must use different consecutive port numbers, such as "6883 6884 6885". Remember to set the Splashtop Streamer and client to these ports as well.
Step 7: Finally, remember to click on "Update" to save all the changes. This will save your settings and restart the router, so your connections will be lost temporarily.
Step 8: Moving to the tablet / phone app — Create an entry on your client by clicking on the "+" near the upper left corner of the Splashtop Remote client (iPad).
Step 9: Make sure to use the external IP address from Step 3. This is where you can enter in your DynDNS address instead of the external IP address, if you have it set up.
NOTE: Again, your external IP address may change, and you will need to update this entry if it does.