Technical data

Configuring the DHCP Client
8.2 DHCP Client Components
8.2.2.3 The Host Name File
You can configure the DHCP client to suggest a host name of your choice to the
DHCP server by entering the name into a file named HOSTNAME.ifname. This
file contains one line of text that contains the unqualified host name to suggest.
You store the file in directory specified by the system logical TCPIP$DHCP_
CONFIG, if defined, or in the SYS$SYSDEVICE:[TCPIP$DHCP] directory.
If you have multiple interfaces and want to suggest a different host name
for each one, put the desired interface host names into separate files called
HOSTNAME.ifname, where ifname is the name of the interface. For example,
if you have two interfaces, WF0 and WE0, and you want the WF0 interface to
receive the host name
myhostfiber and the WE0 interface to receive the name
myhostether , enter the following commands:
$ CREATE SYS$SYSDEVICE:[TCPIP$DHCP]HOSTNAME.WF0
myhostfiber
<CTRL-Z>
$ CREATE SYS$SYSDEVICE:[TCPIP$DHCP]HOSTNAME.WE0
myhostether
<CTRL-Z>
When configuring an interface, the DHCP client will first check for a
HOSTNAME.ifname file and then, if that is not found, for the HOSTNAME.
file.
When you initially configure the DHCP client the value of your node’s SCSNODE
parameter is placed into a file called HOSTNAME. with no .ifname extension.
If you change the HOSTNAME.ifname file, you must delete the interface.DHC file
for the change to take effect.
8.2.2.4 The DHCPTAGS. File
The DHCPTAGS. file identifies the type of each parameter returned to the DHCP
client by the DHCP server. Each supported option consists of the following:
• Option code number
• A two digit mnemonic code
• A short mnemonic text string for use in the DHCPCAP database
• A description of each option
The options are defined as follows:
• Standard
The semantics on which all client and server DHCP implementations agree.
These options are administered by the Internet Assigned Numbers Authority
(IANA). They are numbered from 1 to 127, and 255.
• Site specific
Within a specific site all client and server implementations agree on the
semantics, but at another site the type and meaning of an option may differ.
These options are numbered from 128 to 254.
• Vendor specific
Each vendor may define 256 options unique to that vendor. The vendor is
identified within a DHCP packet by the Vendor Class option (#60). An option
with a specific numeric identifier belonging to one vendor will, in general,
have a type and semantics different from those of another vendor. Vendor
8–10 Configuring the DHCP Client