Table 81: Meaning Of Dhcp Options - WAGO -I/O-SYSTEM 750 Manual

218 Fieldbus Communication
• Automatic assignment
For automatic assignment, a range of IP addresses is assigned on the
DHCP server.
If the address was assigned from this range once to a DHCP client, then it
belongs to the client for an indefinite period as the assigned IP address is
also bound to the MAC address.
Dynamic assignment
•
This process is similar to automatic assignment, but the DHCP server has a
statement in its configuration file that specifies how long a certain IP
address may be "leased" to a client before the client must log into the
server again and request an "extension".
If the client does not log in, the address is released and can be reassigned
to another (or the same) client. The time defined by the administrator is
called Lease Time.
Some DHCP servers also assign IP addresses based on the MAC address,
i.e., a client receives the same IP address as before after longer network
absence and elapse of the Lease Time (unless the IP address has been
assigned otherwise in the mean time).
DHCP is used to dynamically configure the network parameters.
The ETHERNET TCP/IP fieldbus coupler/controller has a DHCP client that
supports the following options in addition to the default "IP address" option:

Table 81: Meaning of DHCP options

Option
[OPT1] Subnet mask
[OPT2] Time zone
[OPT3] Gateway
[OPT6] DNS server
[OPT15] Domain name *
[OPT42] NTP server
[OPT51] Lease time
[OPT58] Renewing time
[OPT59] Rebinding time
)
* In contrast to BootP, the DHCP client does not support assignment of the host name.
Manual
1.5.0
750-882 Media Redundancy ETHERNET Controller
Meaning
32-bit address mask that displays which bits of the IP address
identify the network and which identify the network stations.
Options not supported.
Options not supported.
IP address of the name servers that converts a name into an IP
address. Up to 2 DNS servers can be configured.
)
Options not supported.
Options not supported.
The maximum duration (i.e., how long the fieldbus
coupler/controller maintains the assigned IP address) can be
defined here. The maximum lease time for the fieldbus controller
is 48 days. This is due to the internal timer resolution.
The minimum lease time is 16 minutes.
The renewing time indicates when the fieldbus coupler/controller
must renew the lease time. The renewing time should be
approximately half of the lease time.
The rebinding time indicates after what amount of time the
fieldbus coupler/controller must have received its new address.
The rebinding time should be approximately 7/8 of the lease time.
WAGO-I/O-SYSTEM 750