You can configure the DHCP server to support IPv4 clients that use BOOTP (b ootstrap protocol) or that include the TFTP server name option and boot file name option in their DHCPREQUEST messages. You can specify the name or IP address of the boot server and the name of the file the host needs to boot.
In addition, you can configure the DHCP server to support hosts that use PXE (Preboot Execution Environment) to boot remotely from a server. When such a host starts up, it first requests an IP address so it can connect to a server on the network and download the file it needs to boot. After it downloads the file, the host reboots and sends another IP address request. To better manage your IP resources, set a different lease time for PXE boot requests. You can configure the DHCP server to allocate an IP address with a shorter lease time to hosts that send PXE boot requests, so IP addresses are not leased longer than necessary.
Note
When you assign a failover association to serve DHCP ranges and networks, NIOS denies dynamic BOOTP clients by default, regardless of whether you select or deselect the Deny BOOTP Requests option from Grid Manager. However, if the DHCP ranges or networks are assigned to a single DHCP server (not a failover association), NIOS does not automatically deny dynamic BOOTP clients. In this case, you must manually select the Deny BOOTP Requests option through Grid Manager to ensure that NIOS denies BOOTP requests to avoid problems such as receiving two IP addresses for the same network device.
You can configure BOOTP and PXE properties at the Grid level and override them for members, IPv4 network containers, IPv4 networks, DHCP ranges, fixed addresses, and reservations, host addresses, and roaming hosts. You cannot configure BOOTP and PXE properties for IPv6 DHCP objects.
To configure or override BOOTP and PXE properties:
Note
Enter values in both the Next Server and Boot Server fields if some hosts on your network require the boot server name and others require the boot server IP address.
3. Save the configuration and click Restart if it appears at the top of the screen.
Note that a few characters need manual escaping when you configure a DHCP boot file name, in order to keep the dhcpd.conf file consistent. If you do not use appropriate escape characters, then it might lead to a non working boot file name. The following characters require manual escaping:
'\t'
- Tabulation character'\r'
- Carriage return'\n'
- New line'\b'
- Bell'\xYY
'- YY hex-number (a-f, 0-9)For example, if you set the 'Boot File' to:
'\x86\topdir\subdir\file.img'
You might need to enter \x and \t as the manual escape characters:
'\\x86\\topdir\subdir\file.img'
You can also specify all \ as the manual escape character:
'\\x86\\topdir\\subdir\\file.img'
The above commands result in the underlying dhcpd.conf file:
'\x5cx86\x5ctopdir\\subdir\\file.img'
or
'\x5cx86\x5ctopdir\x5csubdir\x5cfile.img'
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