> For the complete documentation index, see [llms.txt](https://docs.ceruleansonar.com/c/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ceruleansonar.com/c/tracker-650/configuring-the-tracker-650/setting-the-fallback-ip-address.md).

# Setting the Fallback IP Address

The Fallback IP Address is the address used by the Tracker 650 if it is set to get a DHCP address (by setting the static IP to 0.0.0.0) and there is no DHCP server or the DHCP server declines to serve an address. It is your responsibility to make sure it is unique and on the proper subnet. Discussions of subnets are beyond the scope of this manual.

No netmask is necessary.

{% hint style="info" %}
The Tracker 650 will not allow you to set an address starting with 127 or 255. This is to protect you from yourself.
{% endhint %}