D-Link DFL-2500 - Manual (Page 132)

5.5. IP Pools
Overview
IP pools are used to offer other subsystems access to a cache of DHCP IP addresses. These
addresses are gathered into a pool by internally maintaining a series of DHCP clients (one per IP).
The DHCP servers used by a pool can either be external or be DHCP servers defined in
NetDefendOS itself. External DHCP servers can be specified as the server on a specific interface or
by a unique IP address. Multiple IP Pools can be set up with different identifying names.
The primary usage of IP Pools is with IKE Config Mode which a feature used for allocating IP
addresses to remote clients connecting through IPsec tunnels. For more information on this see
Section 9.4.3.4, “Using Config Mode”.
Basic IP Pool Options
The basic options available for an IP Pool are:
DHCP Server behind interface Indicates that the IP pool should use the DHCP server(s)
residing on the specified interface.
Server filter Optional setting used to specify which servers to use. If
unspecified any DHCP server on the interface will be used.
The order of the provided adddress or ranges (if multiple) will
be used to indicate the preferred servers.
Specify DHCP Server Address Specify DHCP server IP(s) in preferred ascending order to be
used. Using the IP loopback address 127.0.0.1 indicates that
the DHCP server is NetDefendOS itself.
Client IP filter Optional setting used to specify which offered IPs are valid to
use. In most cases this will be set to the default of all-nets.
Alternatively a set of IP ranges might be specified. The filter
ensures that only certain IP addresses from DHCP servers are
acceptable and is used in the situation where there might be a
DHCP server response with an unacceptable IP address.
Advanced IP Pool Options
Advanced options available for IP Pool configuration are:
Routing table Policy routing table to be used for lookups when resolving the
destination interfaces for the configured DHCP servers.
Receive interface "Simulated" receive interface. This can be used in policy based routing
rules and/or used to trigger a specific DHCP server rule if the pool is
using a DHCP server in NetDefendOS and the IP address of that server
has been specified as the loopback interface.
MAC Range A range of MAC addresses that will be use to create "fake" DHCP
clients. Used when the DHCP server(s) map clients by the MAC
address. An indication of the need for MAC ranges is when the DHCP
server keeps giving out the same IP for each client.
Prefetched leases Specifies the number of leases to keep prefetched. Prefetching will
improve performance since there won't be any wait time when a system
requests an IP (while there exists prefetched IPs).
Maximum free The maximum number of "free" IPs to be kept. Must be equal to or
5.5. IP Pools Chapter 5. DHCP Services
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