DHCP

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The DS supports Dynamic Host Configuration Protocol (DHCP). DHCP is used to automatically configure the following settings: IP-address (IP), Gateway IP-address (GI), and Netmask (NM). For the DHCP to work there must be a DHCP server on the network where the DS is installed.

 

The DHCP is enabled and disabled through the DHCP (DH) setting. When  DHCP (DH) settingis at 1 (enabled) the DS uses DHCP protocol to obtain its IP-address immediately upon startup. The DS does not start its normal operation until it receives an IP-address from the DHCP server. Gateway IP-address and netmask configuration is optional so the DS does not require these two parameters to be received from the DHCP server.

 

 

LED_IP_not_obtained"IP-address not obtained" pattern is displayed by the status LED's of the DS while the IP-address is being configured through DHCP. This condition corresponds to the value '*' of the i flag returned by the Echo (X) command.

 

 

When requesting an IP-address for itself, the DS asks for a maximum possible lease time (this is the period of time during which the DS will be allowed to use the IP-address). The DS memorizes the lease time actually offered by the DHCP server and applies for a lease extension well before the lease expires. If the lease is extended the DS continues normal operation. If the lease is not extended the DS reboots.

 

While communicating with the DHCP server, the DS supplies its name. The name consists of the values of Owner Name (ON) and Device Name (DN) settings joined by hyphen. For example, the name might look like this:

 

abccorp-dev1

 

Names supplied by DHCP clients are usually supplied (by the DHCP server) to a local DNS server (DNS and DHCP servers often work together on the same physical server PC). This typically allows you to "see" your DS as a member of your local workgroup, for example:

 

abccorp-dev1.workgroup1.mainserver

 

When using DHCP the DS detects Ethernet cable disconnects and re-requests its IP-address from the DHCP server once the cable is plugged back in. The following outcomes are possible:

 

If the DHCP server confirms that the IP-address that was leased to this DS can still be used the DS continues uninterrupted operation

 

If the DHCP server informs the DS that the IP-address that was leased to this DS can no longer be used the DS reboots (naturally, this aborts any data communications in progress). During the boot process the DS will attempt to interact with the DHCP server repeatedly until the IP-address of the DS is properly configured

 

If there is no reply from the DHCP server the DS repeats its request. If there is still no reply the DS reboots. During the boot process the DS will attempt to interact with the DHCP server repeatedly until the IP-address of the DS is properly configured.