Siemens SIMATIC NET SCALANCE W760 Series Configuration Manual page 29

Standard values of the community strings:
● public
has only read permissions
● private
has read and write permissions
Note
Because the SNMP community strings are used for access protection, do not use the
standard values "public" or "private". Change these values following the initial
commissioning.
Further simple protection mechanisms at the device level:
● Allowed Host
The IP addresses of the monitoring systems are known to the monitored system.
● Read Only
If you assign "Read Only" to a monitored device, monitoring stations can only read out
data but cannot modify it.
SNMP data packets are not encrypted and can easily be read by others.
The central station is also known as the management station. An SNMP agent is installed on
the devices to be monitored with which the management station exchanges data.
The management station sends data packets of the following type:
● GET
Request for a data record from the agent
● GETNEXT
Calls up the next data record.
● GETBULK (available as of SNMPv2)
Requests multiple data records at one time, for example several rows of a table.
● SET
Contains parameter assignment data for the relevant device.
The SNMP agent sends data packets of the following type:
● RESPONSE
The agent returns the data requested by the manager.
● TRAP
If a certain event occurs, the SNMP agent itself sends traps.
SNMPv1 and SNMPv2 and SNMPv3 use UDP (User Datagram Protocol). The data is
described in a Management Information Base (MIB).
SCALANCE W760/W720 to IEEE 802.11n Web Based Management
Configuration Manual, 11/2014, C79000-G8976-C350-03
Technical basics
3.5 SNMP
29