With POWER6, the default addresses of the service processors have changed. This only applies to environments where the managed system was powered on before the HMC was configured to act as an DHCP server. The Service Processors may get their IP-Addresses by three different mechanisms:

1. Addresses received from a DHCP Server.
2. Fixed addresses given to the interfaces using the ASMI.
3. Default addresses if neither of the possibilities above is used.

The default addresses are different betweeen POWER5 and POWER6 servers. With POWER5 we have the following addresses:

Port HMC1: 192.168.2.147/24
Port HMC2: 192.168.3.147/24

The POWER6 systems use the following addresses:

First Service Processor:
Port HMC1: 169.254.2.147/24
Port HMC2: 169.254.3.147/24

Second Service Processor:
Port HMC1: 169.254.2.146/24
Port HMC2: 169.254.3.146/24

Link: System p Operations Guide for ASMI and for Nonpartitioned Systems.

Older pSeries systems (Power4) are equipped with environmental sensors. You can read the sensor values using:

# /usr/lpp/diagnostics/bin/uesensor -l

You can use these sensors to monitor your systems and your computer rooms. It isn't very difficult to create a script to monitor these environmental sensors regularly and to display it on a webpage, updating it automatically. Newer systems (LPAR based) are not equipped with these environmental sensors. For PC systems several products exist, which attach to either a RJ45 or a parallel port and which can be used to monitor temperatures.