Occasional power failures can cause your router to reboot while you are away from home, causing its IP address to change. When this occurs, you will no longer have access to the ISY until you determine the new IP address and update whatever software you are using to access it.
There are sites out there such as www.dyndns.com that allow you to assign a static domain name to your router so that when you do get a new IP address, either your router or your PC will associate your domain with the new IP address. The problem with this is that it either requires a router that supports this handy feature or you must leave a PC on all the time to monitor any changes.
My Verizon Westel 327W router does not support the function and I don't want to leave my PC on all the time, so I came up with this simple solution:
1) Set up the ISY's email notification feature in "Configuration"
2) Set up a new program that simply says something like "If time is 8:00am, Notify [your email]". I set mine up for multiple notifications, at 8am, 2pm, and 8pm.
3) If you don't want to be bothered by actually seeing these emails in your Inbox, set up a folder something like "ISY IP broadcasts" and set up a rule to move these emails to that folder when they arrive.
Now, if you are ever away from home and find you do not have access to the ISY, you can open the most recent email and view the header to ascertain the IP address.
Note that the method to view the header will vary by the product you are using, and it even differs between Outlook 2007 and Outlook 2010. To save you that headache, here's how to find the "Internet headers" in either of those:
Outlook 2007:
1) Open the email
2) Open the "Options" dialog box by clicking the arrow in the lower right corner of the "Options" section on the ribbon
Outlook 2010:
1) Open the email
2) Click "File", then click the "Properties" button in the lower section of the right panel.
For whatever product you are using, I recommend that when you get your first email, you determine your current IP address and find it in your header right away so you know where it is when you need it.
I don't know if UDI has access to the current IP address from the device, but if they do and since the latest firmware version allows variables to be inserted in the emails, the IP address would be a great one to add. This would eliminate the entire header interrogation process.
I hope you find this helpful,
Jim