Device does not get IP address from DHCP server
DHCP in SIR, Lukas and SAS2xx devices works as follows.
When a device is powered off, then it will try to get configurations from DHCP server with a timeout of 20 seconds.
If configuration from DHCP fails, then no retries are done. It will only broadcast a DHCP discovery again the next time it powers off.
Until the next attempt at power off, the device will use the old IP configuration. Such behavior can cause problem expecially during installation but also in general. There is a good chance that the old IP settings are not suitable for the network (e.g., when the device is placed in a new network).
One scenario which is sure to fail is if the device is powered before the network cable is connected. Connecting the cable 20 seconds later or even less (the device needs a few seconds to complete DHCP configuration, while the timeout is fixed at 20 sec) after the power will be a guaranteed failure to get an IP address from DHCP.
- The best tip for installation is to always connect the network cable before the power
- It is unfortunately not possible to see whether DHCP succeeded (except from STP logs). It could help that after the device is installed and user has gone through the installation wizard, to always reset the device one time.