NEXCOM IFA 1610 - Manual (Page 41)

Copyright © 2014 NEXCOM International Co., Ltd. All Rights Reserved. IFA 3610/IFA 2610/IFA 1610 User Manual
Chapter 4: The Services Menu
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The following parameters can be set for fixed leases:
MAC address
The client’s MAC address.
IP address
The IP address that will always be assigned to the client.
Description
An optional description of the device receiving the lease.
Next address
The address of the TFTP server. This and the next two options are useful only in a few cases (see below for an example).
Filename
The boot image file name. Option needed only for thin clients or network boot.
Root path
The path of the boot image file.
Enabled
If this checkbox is not ticked, the fixed lease will be stored but not written down to the file
dhcpd.conf.
The actions available for each fixed lease in the table are:
▪ - toggle the status of the lease, enabled or disabled.
▪ - modify the property of the lease.
▪ - remove the lease.
A use case for a fixed lease.
A use case that shows the usefulness of a fixed lease is the case of thin clients or disk-less workstations on the network
that use PXE, i.e., boot the operating system from an image supplied by a networked tftp server. If the tftp server is
hosted on the same server with the DHCP, the thin client receives both the lease and the image from the same server.
More often, however, the tftp server is hosted on another server on the network, hence the client must be redirected
to this server by the DHCP server, an operation that can be done easily adding a fixed lease on the DHCP server for the
thin client, adding a next-address and the filename of the image to boot.
Besides the information supplied during the fixed lease creation, the list allow each lease to be enabled or disabled (by
ticking the checkbox), edited, or deleted, by clicking on the icons in the Actions column. Editing a lease will open the
same form as the creation of a new lease, whereas deleting a lease will immediately remove it from the configuration.
Note: All leases assigned by the DHCP server are stored by default in the /var/lib/dhcp/dhcpd.leases file.
Although the DHCP daemon takes care of cleaning that file, it may happen that the file stores lease that have already
been expired and are quite old. This is not a problem and does not interfere with the normal DHCP server working. A
typical entry in that file is:
lease 192.168.58.157 {
starts 2 2013/06/11 13:00:21;
ends 5 2013/06/14 01:00:21;
binding state active;
next binding state free;
hardware ethernet 00:14:22:b1:09:9b;
}
Current dynamic leases
When the DHCP server is active, and at least one client has received a (dynamic) IP address, a third box appears at the
bottom of the page, containing the list of the currently assigned dynamic IP addresses. This list report the IP address, the
MAC address, the hostname, and the expiry time of the lease associated to each client.