Configuration and operation 
  6.1 Security recommendations 
CP 343-1 
Manual, 12/2018, C79000−G8976−C201-08 
45 
● 
 
–  Open 
The port is open at the start of the configuration. 
–  Closed 
The port is closed at the start of the configuration. 
●   
 
–  Open 
The port is always open and cannot be closed. 
–  Open after configuration 
The port is open if it has been configured. 
–  Open (login, when configured) 
As default the port is open. After configuring the port, the communications partner 
needs to log in. 
–  Open with block call 
The port is only opened when a suitable program block is called. 
● 
 
Specifies whether or not the protocol authenticates the communications partner during 
access. 
 
S7 and online 
connections 
102 (TCP)  Open  Open after configuration  No 
Ports of communication partners and routers 
Make sure that you enable the required client ports in the corresponding firewall on the 
communications partners and in intermediary routers. 
These can be: 
●  NTP / 123 (UDP) 
●  DNS / 53 (UDP) 
●  DHCP / 67, 68 (UDP)