When you can't access HP ILO via Web Console anymore (e.g. because you have configured the IP address wrongly or enabled DHCP by accident), there is a possibility to configure the ILO IP settings via ESX.
Login to the ESX vSphere Client
Make sure that SSH is running on ESX (ESX host > Configuration > Security Profile > Services > Properties, Start SSH if it is not started)
Download Putty on the Windows machine where the vSphere Client runs. Start Putty.exe and use the IP address of the ESX host to login.
After you have entered the user name (root), it takes a while for the password prompt to be shown. Wait and then enter the password.
Export the current config: ./hponcfg -w /tmp/ilo_config.txt
Now, copy this file to the Windows machine (for example with WinSCP).
Open it with WordPad and change the following lines:
<IP_ADDRESS VALUE = “10.10.10.20″/>
<SUBNET_MASK VALUE = “255.255.255.0″/>
<GATEWAY_IP_ADDRESS VALUE = “10.10.10.1″/>
<DHCP_ENABLE VALUE = “N”/>
Copy it back to the ESX host (overwrite existing file)
./hponcfg -f /tmp/ilo_config.txt
Let the ILO restart.
You should now be able to login to ILO via the Web Console.