Siemens SIMATIC NET SCALANCE M826 Operating Instructions Manual page 13

Secure/non-secure protocols
● Avoid or disable non-secure protocols, for example Telnet and TFTP. For historical
reasons, these protocols are still available, however not intended for secure applications.
Use non-secure protocols on the device with caution.
● Avoid or disable non-secure protocols. Check whether use of the following protocols is
necessary:
– Broadcast pings
– Non authenticated and unencrypted interfaces
– ICMP (redirect)
– LLDP
– Syslog
– DHCP Options 66/67
– TFTP
● The following protocols provide secure alternatives:
– SNMPv1/v2 → SNMPv3
– HTTP → HTTPS
– Telnet → SSH
– TFTP → SFTP
● Use secure protocols when access to the device is not prevented by physical protection
measures.
● To prevent unauthorized access to the device or network, take suitable protective
measures against non-secure protocols.
● If you require non-secure protocols and services, activate these at interfaces that are
located within a protected network area.
● Using a firewall, restrict the services and protocols available to the outside to a minimum.
● For the DCP function, enable the "DCP read-only" mode after commissioning.
SCALANCE M826
Operating Instructions, 08/2018, C79000-G8976-C362-05
Check whether use of SNMPv1 is necessary. SNMPv1 is classified as non-secure.
Use the option of preventing write access. The product provides you with suitable
setting options.
If SNMP is enabled, change the community names. If no unrestricted access is
necessary, restrict access with SNMP.
Security recommendations
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