I have a Sagem router and I manage a mainly Mac network: laptop, desktop, iPhone and iPod Touches, plus an Xbox, network printer, SlingBox and a WD NAS.

This network is managed over a wi-fi and powerline (devolo) ethernet network.

With all this running, I expected to see a shedload of MAC addresses with IP addresses in the 'Attached Devices' list, but only ever see 5-6. For example, the printer has an IP address, but isn't shown on the attached devices list. The NAS periodically appears on the list, but is present on the network as I am backing up to it (I need to give it a static IP address though). The devolo ethernet ports don't show at all, neither does an additional Apple airport which is attached via a powerline and ethernet switch (in the same place as the Xbox - which does usually appear).

Any thoughts as to why things have IP addresses but do not appear on the list?