The firewall is enabled by default. In the delivery state (factory setting), the configuration of the
predefined IPv4 rules is as follows:
Service
Access
Local access (vlan1) to the de‐
vice
1)
External access to the device
M87x, M81x: ppp0/usb0
S615:vlan2
Cloud Connector
✓
-
DHCP
✓
✓ (only with S615)
DNS
✓
--
HTTP
✓
--
HTTPS
✓
--
IPsec VPN
--
✓
Ping
✓
--
SMS relay (only with M87x)
✓
--
SNMP
✓
--
SSH
✓
--
System Time
--
--
Telnet
✓
--
VRRP
--
--
1)
With SCALANCE M826 and M804PB, only vlan1 is available in the delivery state.
3.5.3
NAT
NAT (Network Address Translation) is a method of translating IP addresses in data packets.
With this, two different networks (internal and external) can be connected together.
A distinction is made between source NAT in which the source IP address is translated and
destination NAT in which the destination IP address is translated.
You will find information on NAT scenarios that are implemented with the device at the following
https://support.industry.siemens.com/cs/gb/en/view/109744660
IP masquerading
IP masquerading is a simplified source NAT. With each outgoing data packet sent via this
interface, the source IP address is replaced by the IP address of the interface. The adapted
data packet is sent to the destination IP address. For the destination host it appears as if the
queries always came from the same sender. The internal nodes cannot be reached directly
from the external network. By using NAPT, the services of the internal nodes can be made
reachable via the external IP address of the device.
IP masquerading can be used if the internal IP addresses cannot or should not be forwarded
externally, for example because the internal network structure should remain hidden.
You configure masquerading in "Layer 3" > "NAT" > "IP Masquerading (Page 236)".
Technical basics
3.5 Security functions
SCALANCE S615 Web Based Management
Configuration Manual, 11/2019, C79000-G8976-C388-08
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