3Com OfficeConnect 3C855 User Manual page 35

Navigating Through the Gateway Configuration Pages 35
each device that is connected to the LAN, the IP address, Host Name and MAC
address of that device is displayed. As you connect more devices to the LAN, the
client list will grow to a maximum number of clients, which is determined by the IP
address range.
The Release button allows the lease time for the IP address that has been issued to
a device to be cleared. The lease time is set at 12 hours. If a PC has been switched
off, using the Release Button would allow the 12 hour lease time to be cleared.
The IP address would then be available for another device if there were no other IP
addresses available.
As the IP address is fixed to a MAC address, then each PC will normally be issued
with the same IP address. The only time that a PC will get a different IP address is
if the unit is reset to factory defaults or the DHCP server has run out of IP
addresses and another IP address has been released or has expired after 12 hours.