● There is normally no fixed address assignment; in other words, when a client requests an
IP address again, it normally receives a different address from the previous address. It is
possible to configure the DHCP server so that the DHCP client always receives the same
fixed address in response to its request. The parameter with which the DHCP client is
identified for the fixed address assignment is set on the DHCP client. The address can be
assigned via the MAC address, the DHCP client ID, PROFINET device name or the device
name. You configure the parameter in "System > DHCP Client (Page 174)".
● The following DHCP options are supported:
– DHCP option 3: Assignment of a router address
– DHCP option 6: Assignment of a DNS server address
– DHCP option 66: Assignment of a dynamic TFTP server name
– DHCP option 67: Assignment of a dynamic boot file name
Note
DHCP uses a mechanism with which the IP address is assigned for only a short time (lease
time). If the device does not reach the DHCP server with a new request on expiry of the lease
time, the assigned IP address, the subnet mask and the gateway continue to be used.
The device therefore remains accessible under the last assigned IP address even without
a DHCP server. This is not the standard behavior of office devices but is necessary for
problem-free operation of the plant.
5.2.4
Address assignment with the Primary Setup Tool
Introduction
The PST (Primary Setup Tool) is capable of assigning such an address to unconfigured devices
that do not yet have an IP address.
Requirement
The devices can be reached via Ethernet.
Note
For more detailed information, refer to the Primary Setup Tool configuration manual.
You will find the PST at Siemens Industry Automation and Drives Service & Support on the
Internet under the entry ID 19440762. You can access this entry at the following URL:
PST (
https://support.industry.siemens.com/cs/ww/en/view/19440762
IP addresses
5.2 IPv4 address
SCALANCE W1780/W1740 according to IEEE 802.11ac Web Based Management
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