Novell NETWARE 6-DOCUMENTATION Manual page 1640

Table 8
66
Novell DNS/DHCP Management Utility Administration Guide
If your typical server outage lasts two hours, a lease of four hours would
avoid loss of lease to clients that were active at the time of the server
outage.
We recommend setting your lease times to twice the length of a typical
server outage.
The same recommendation applies to communications line outages. If a
communications line is down long enough that leases expire, you might
see a significant network load when the service is restored.
How long can your clients operate without access to the DHCP server?
If you have users who require a lease for important job functions, consider
lease times for them that are twice the length of a maximum server
outage. For example, if your DHCP server were to go down on Friday
evening and require the entire workday Monday to be restored, that would
be an outage of three days. In this case, a six-day lease covers that
situation.
Do you have users who advertise their IP addresses for services they
render?
If you have users setting up Web pages or archiving data for others to
access, they want addresses that do not change. You might want to assign
permanent addresses for these users instead of assigning long lease times
(three weeks or two months, for example).
The relevant length of time is the maximum amount of time you want to
allow a client to keep an address, even if the host computer is turned off.
For example, if an employee takes a four-week vacation and you want the
employee to keep his or her address, a lease of eight weeks or longer is
required.
Table 8 lists examples of lease times and reasons why these times were
chosen.
Lease Time Examples
Lease Time
15 minutes
Rationale
Keeps the maximum number of
addresses free when there are more
users than available addresses, but
results in significant traffic and
frequent updates to eDirectory