3Com OfficeConnect User Manual page 43

Figure 36 DHCP Clients Screen
The Router grants leases for 7 days. If a computer does not
connect for a week, its IP Address may be reused.
The Router will attempt to supply a computer the same lease as
was issued previously, even if that lease has expired.
Expired leases are only reused when there are no free leases
available. When an expired lease is re-issued the oldest lease that
is not a fixed association is used.
The Release button allows the lease for an IP address that has
been issued to a device to be cleared. If you are running short of
addresses in the DHCP Pool and you know of computers that are
unlikely to connect to your network soon you can release the IP
address allowing it to be reallocated to another machine.
If you have spare or expired IP addresses in the pool you will not
need to release addresses.
The IP Address, Host Name and MAC Address indicate the
address that has been allocated. They identify the machine by
name and by the unique number (MAC Address) of the
machine's network card.
The Fixed Association check box allows you to freeze the
relationship between an IP address and a particular machine. If
you check the box for one row, that IP address will always be
given out to the same machine and will not be allocated to
another machine even if the lease has expired. Clear the check
box to allow the address to revert back to normal behavior.
Click Refresh to save any changes you have made.
Click New to allocate an IP address to a MAC address. Click Add
to save.
Figure 37 Fixed DHCP Mapping Screen
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