Quick Start Guide REX 200/250 3G | LTE
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8. Remote maintenance of Ethernet CPUs
Notes:
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The LAN ports are suitable for 100 mbps and full duplex operation, and support
auto-crossover and auto-negotiation. No special PROFINET functions are supported.
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When connecting additional Ethernet participants (PLC/panel) on the REX 200/250,
it must be ensured that the IP addresses of the devices lie within the address range of
the LAN interface of the REX 200/250.
Device settings: Services – Firewall Settings – SNAT
With a REX 200/250, the SNAT function is activated as a default. With this setting,
participants for which no gateway*/router has been entered are reached via the VPN
tunnel. For the CPUs and panels of some manufacturers, it can be the case that you
need to explicitly enter the gateway* and deactivate the SNAT function in order that
a remote connection with the end device is possible.
*Gateway: This refers to the LAN IP address of the REX 200/250.
In order to reach a PLC or a panel via the VPN tunnel, the OpenVPN adapter must be
selected in the corresponding engineering tool as the interface. The virtual network
connection responsible for this is the TAP Windows
1
Adapter V9.
The setting to be selected in the PG/PC interface module from the SIMATIC STEP 7
2
software is emphasized in the detail to the right.
