D-Link DFL-260E User Manual for DFL-260E - Page 260
Memory Allocation for Prefetched Leases, Listing IP Pool Status, Receive Interface, MAC Range
View all D-Link DFL-260E manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 260 highlights
5.4. IP Pools Chapter 5. DHCP Services Receive Interface MAC Range Prefetch leases Maximum free Maximum clients Sender IP A "simulated" virtual DHCP server receiving interface. This setting is used to simulate a receiving interface when an IP pool is obtaining IP addresses from internal DHCP servers. This is needed since the filtering criteria of a DHCP server includes a Receive Interface. An internal DHCP server cannot receive requests from the IP pool subsystem on an interface since both the server and the pool are internal to NetDefendOS. This setting allows such requests from a pool to appear as though they come from a particular interface so that the relevant DHCP server will respond. 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. Specifies the number of leases to keep prefetched. Prefetching will improve performance since there will not be any wait time when a system requests an IP (while there exists prefetched IPs). The maximum number of "free" IPs to be kept. Must be equal to or greater than the prefetch parameter. The pool will start releasing (giving back IPs to the DHCP server) when the number of free clients exceeds this value. Optional setting used to specify the maximum number of clients (IPs) allowed in the pool. This is the source IP to use when communicating with the DHCP server. Memory Allocation for Prefetched Leases As mentioned in the previous section, the Prefetched Leases option specifies the size of the cache of leases which is maintained by NetDefendOS. This cache provides fast lease allocation and can improve overall system performance. It should be noted however that the entire prefetched number of leases is requested at system startup and if this number is too large then this can degrade initial performance. As leases in the prefetch cache are allocated, requests are made to DHCP servers so that the cache is always full. The administrator therefore has to make a judgement as to the optimal initial size of the prefetch cache. Listing IP Pool Status The CLI command ippools can be used to look at the current status of an IP pool. The simplest form of the command is: gw-world:/> ippool -show This displays all the configured IP pools along with their status. The status information is divided into four parts: • Zombies - The number of allocated but inactive addresses. • In progress - The number of addresses that in the process of being allocated. • Free maintained in pool - The number of addresses that are available for allocation. • Used by subsystems - The number of addresses that are allocated and active. 260