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DHCP Option 61 (Client Identifier)
The DHCP Option 61 (Client Identifier) allow the end-user to specify a unique identifier, which has to be
unique within the DHCP domain.
Attribute #22 (DHCP Option 61 source) is used to configure the source of the Client Identifier. The table below
shows the definition for the Client identifier for different sources and their description.
Value
Source
Description
0
Disable
The DHCP Option 61 is disabled. This is the default value if the attribute is not imple-
mented in the application.
1
MACID
The MACID will be used as the Client Identifier
2
Host Name
The configured Host Name will be used as the Client Identifier
3
Generic String
Attribute #23 will be used as the Client Identifier
Attribute #23 (DHCP Option 61 generic string) is used to set the Client Identifer when Attribute #22 has been
set to 3 (Generic String). Attribute #23 contains the Type field and Client Identifier and shall comply with the
definitions in RFC 2132. The allowed max length that can be passed to the module via attribute #23 is 64
octets.
Example:
If Attribute #22 has been set to 3 (Generic String) and Attribute #23 contains 0x01, 0x00, 0x30, 0x11, 0x33,
0x44, 0x55, the Client Identifier will be represented as an Ethernet Media Type with MACID
00:30:11:33:44:55.
Example 2:
If Attribute #22 has been set to 2 (Host Name) Attribute #23 will be ignored and the Client Identifier will be the
same as the configured Host Name.
Anybus
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CompactCom
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40 Modbus-TCP
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Transparent Ethernet Network Guide
SCM-1202-022 1.1