FYI: The tivo (as will most linux systems) remembers it's last lease across reboots. When it comes up, instead of doing a DISCOVER (tell me what I should use) - it first does a REQUEST (may I have this address please?) for the last address it had. Only if that REQUEST is ignored, or more appropriately NAKed, will it then go back to DISCOVER.
This is normally a good thing, as for as long as that lease is available, the Tivo will tend to come back up at the same address, even if the lease has expired. (If the address has been given to someone else in the meanwhile, the DHCP server will respond with a NAK, forcing a full DISCOVER).
In the cases where you want to shake the tivo off of that address, it can be annoying, and dhcp sever specific. You need to get the dhcp server to say NO when the tivo comes up asking if it may use that address again. (Block it, reserve it for another mac, change the dhcp pool range, etc...)
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