● NTP (secure)
For secure transfer during time-of-day synchronization
● Protection for devices and network segments
The protection provided by the firewall can cover individual devices, several devices or
even entire network segments.
Plants with security requirements - recommendation
Use the following options:
• If you have systems with high security requirements, use the secure protocols
NTP (secure) and HTTPS.
• If you connect to public networks, you should use the firewall. Think about the services
you want to allow access to the station via public networks. By using the "bandwidth
limitation" of the firewall, you can restrict the possibility of flooding and DoS attacks.
For information on configuring the security functions, refer to the section Security functions
You will find further information on the functionality and configuration of the security functions
in the information system of STEP 7 and in the manual /2/ (Page 70).
Configuration limits and performance data
Number of CMs/CPs per station
In each S7-1200 station, up to three CMs/CPs can be plugged in and configured; this allows
three CP 1243-1 PCC modules.
● TCP connections
The CP can establish connections to up to 8 communications partners (S7 stations).
● Online functions
1 connection resource is reserved for online functions.
● S7 connections
8 connection resources for S7 connections (PUT/GET)
● PG/OP connections
– 1 connection resource for PG connections
– 3 connection resources for OP connections
CP 1243-1 PCC
Operating Instructions, 02/2015, C79000-G8976-C384-01
Application and properties
1.5 Configuration limits and performance data