The reason you can't change the IP address or other i.LON parameters through the i.LON Web pages is most likely due to using the wrong Web browser, browser version or browser setting.
i.LON 600 works with IE6, IE7, and IE8, older versions of IE 11 (version 11.0.9600.16428, using IE7 emulation mode), and Mozilla FireFox (3.0 or higher, with the IETab plugin). On newer PCs you can consider using a Virtual Machine (VM) with the older Web browser versions.
The easiest way to change the i.LON 600 IP address is to change it through the i.LON 600 console, but to do so you will need local access to the i.LON and a null modem cable (may require a USB-to-serial cable on newer PCs).
i.LON 600 Console:
You can also change the i.LON 600 IP address by connecting a 9-pin null modem RS-232 cable (may require a USB-to-serial cable on newer PCs) to the i.LON 600 console port and using a terminal emulation program like PUTTY or teraterm. Issue "show" or "show all" to see IP addresses. Issue "help" or "help all" to see console commands. Use "ipaddress, gateway and subnetmask commands to change the IP settings, issue "show" to confirm and then reboot i.LON for changes to take affect. For example:
IE11 requires IE7 emulation:
Older versions of IE11 (11.0.9600.16428) work, but newer version of IE11 (11.0.1024240.16431) and the one that comes with Microsoft Edge does not work.
In IE go to "Settings > F12 Developer mode > Emulation menu [looks like desktop PC]", set Document mode to "7", and User agent string to "Internet Explorer 7". These settings do not get stored, so keep the F12 Developer window open during the entire time you use IE11.
See KB930 for supported Web Browsers for all Echelon Products.
Supported Web Browsers (KB930)