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Testing for failures

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I want to setup some tests to make sure a firewall isn't leaking. For this, I need to count a failure to connect as a success and a connection as a failure. Is there a way to do this with standard sensors?

firewall leak-testing sensor-failure

Created on Dec 8, 2016 10:22:35 PM



6 Replies

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What exactly do you need not to connect? Open a connection to a port? If so, you could use the port sensor which allows to select the desired state.

Created on Dec 9, 2016 11:31:40 AM by Stephan Linke [Paessler Support]



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Thanks, that's exactly what I was looking for!

Created on Dec 9, 2016 7:16:28 PM



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Glad I could be of assistance! :)

Created on Dec 12, 2016 6:02:31 AM by Stephan Linke [Paessler Support]



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Just remember, if PRTG is on the LAN side of your firewall, even if you are probing the external IP of your router/firewall the same firewall rules may not apply.

For example it's possible you allow SMTP on port 25 from external to your external IP,but not from internal address. In this case PRTG would see the port closed (and secure), but its really open.

I suggest you (ALSO) use external services (like https://pentest-tools.com/network-vulnerability-scanning/tcp-port-scanner-online-nmap or http://mxtoolbox.com/portscan.aspx) to run port scans from the outside in.

Created on Dec 12, 2016 11:43:51 PM



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Thanks for the small guide, Andrew! :)

Created on Dec 13, 2016 9:21:51 AM by Stephan Linke [Paessler Support]



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We have a remote probe at rackspace for external testing like this

Created on Dec 14, 2016 8:31:59 PM




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