Siemens S7-300 Configuration Manual page 106

Configuring communications connections
5.7 Configuring UDP connection properties
Ports
The ports or port addresses define the access point to the user program within the station /
CPU. They must be unique within the station / CPU!
The following table shows the range of values:
Application / note
Fixed; must not be modified!
Default assignment; should not be used (well-known ports)
Range used by STEP 7 in which a free port address is searched
for and assigned.
The following local port numbers are reserved. Do not use this in the connection
configuration.
Table 5- 5
Unspecified UDP connection
An unspecified UDP connection can be used in two ways:
● Free UDP connection
To configure a free UDP connection, select the "Address assignment in block" check box.
The input boxes for the remote IP address and the remote port are then deactivated since
the destination addresses are now specified by the user program.
● Connection to a "remote station" in a different project
You can specify the remote IP address and the port for any destination station. The
destination station can be in the current STEP 7 project or in another project.
Note the following:
Since there is no connection establishment with UDP (datagram service), communication
via the configured UDP connection is only possible if the partner addresses (IP address
and port) are specified.
106
Reserved port numbers
Port number
161
500
3820
4500
34964
65532
65533
65534
65535
Protocol
UDP SNMP_REQUEST
UDP ISAKMP (Internet Security Association and Key
Management Protocol)
UDP SCP (Security Configuration Protocol)
UDP IPSec NAT Traversal
UDP PN IO
UDP NTP
UDP NTP
UDP NTP
UDP NTP
Configuring and commissioning S7 CPs for Industrial Ethernet
Configuration Manual, 09/2013, C79000-G8976-C182-13
Port addresses
0
1..1024
2000 or higher
Service