Understanding IP Addressing B-7
Configuration
This section describes the specific IP address lease, renew, and release mechanisms for both the Mac and PC,
with either DHCP or MacIP address serving.
DHCP address serving
Windows 95 workstation:
• The Win95 workstation requests and renews its lease every half hour.
• The Win95 workstation does NOT relinquish its DHCP address lease when the machine is shut down.
• The lease can be manually expired using the WINIPCFG program, a command line program executable from
the DOS prompt or from the START:RUN menu on a Windows-based computer.
Windows 3.1 workstation (MSTCP Version 3.11a):
• The Win3.1 workstation requests and renews its lease every half hour.
• The Win3.1 workstation does NOT relinquish its DHCP address lease when the user exits Windows and
goes to DOS.
• The lease can be manually expired by typing IPCONFIG/RELEASE from a DOS window within Windows or
from the DOS prompt.
Macintosh workstation (Open Transport Version 1.1 or later):
• The Mac workstation requests and renews its lease every half hour.
• The Mac workstation relinquishes its address upon shutdown in all but one case. If the TCP/IP control
panel is set to initialize at startup, and no IP services are used or the TCP/IP control panel is not opened,
the DHCP address will NOT be relinquished upon shutdown. However, if the TCP/IP control panel is opened
or if an IP application is used, the Mac WILL relinquish the lease upon shutdown.
• If the TCP/IP control panel is set to acquire an address only when needed (therefore a TCP/IP application
must have been launched to obtain a lease) the Mac WILL relinquish its lease upon shutdown every time.
Netopia Firmware Version 8.4 DHCP server characteristics
• The Netopia Firmware Version 8.4 ignores any lease-time associated with a DHCP request and
automatically issues the DHCP address lease for one hour.
• The number of devices a Router can serve DHCP to is 512. This is imposed by global limits on the size of
the address serving database, which is shared by all address serving functions active in the gateway.
• The Router releases the DHCP address back to the available DHCP address pool exactly one hour after the
last-heard lease request. Some other DHCP implementations may hold on to the lease for an additional
time after the lease expired to act as a buffer for variances in clocks between the client and server.
MacIP serving
Macintosh workstation (MacTCP or Open Transport):
Once the Mac workstation requests and receives a valid address, the Router actively checks for the
workstation’s existence once every minute.
