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PRTG try to attempt the devices via file share ports



Hello everybody. PRTG try to access the network devices which should be monitored via port 445, 135 and 139 (file share). The ports are blocked by our firewall and looks like an attack. Why does PRTG use this ports and how can I stop it?

Thanks for your answers in advance Br Christoph

445 file-share prtg

Created on Dec 1, 2021 9:22:45 AM

3 Replies



Which sensors are you using? This does seems like you are using any SMB sensors on this device. TCP port 135 is also used by WMI.
You can stop it by deleting or pausing sensors underneath the affected device.

Created on Dec 3, 2021 11:47:26 AM by  Timo Dambach [Paessler Support]



Hello, Thank you for your answer. I am only using SNMP sensors. For example the standard template for CISCO devices.

Created on Dec 3, 2021 12:13:32 PM



Hello Christoph,

In this case please

1) head to "Setup > System Administration > Monitoring" and disable the "Recommended"- and "Similar"- Sensors Detection Feature for testing purposes
2) also head to the "settings"-tab of your device and disable "System information" and "similar sensors detection" in the "Advanced Network Analysis" section here as well

as these features might use those ports as well. If the issue persist, feel free to send us screenshots of the issue, device & settings to [email protected] so we can take a closer look.

Created on Dec 8, 2021 8:39:14 AM by  Timo Dambach [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.