Symptoms

There are Java exceptions in discovery logs for Network devices(Routers and switches).

java.lang.IllegalArgumentException: Missing required parameterip_address
at com.service_now.mid.probe.shazzam.scanners.APortScanner.getParamAsIP(APortScanner.java:208)
at com.service_now.mid.probe.shazzam.scanners.APortScanner.init(APortScanner.java:56)
at com.service_now.mid.probe.shazzam.scanners.AUDPPortScanner.init(AUDPPortScanner.java:35)
at com.service_now.mid.probe.shazzam.scanners.DNS.init(DNS.java:63)
at com.service_now.mid.probe.DNS.addScanners(DNS.java:140)
at com.service_now.mid.probe.DNS.processChunk(DNS.java:114)
at com.service_now.mid.probe.ShazzamBase.syncProcessChunk(ShazzamBase.java:71)
at com.service_now.mid.probe.DNS.probe(DNS.java:90)
at com.service_now.mid.probe.AProbe.process(AProbe.java:84)
at com.service_now.mid.queue_worker.AWorker.runWorker(AWorker.java:125)
at com.service_now.mid.queue_worker.AWorkerThread.run(AWorkerThread.java:20)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

Release

Jakarta and Kingston.

Cause

The cause of this problem is both sensors and patterns enabled at the same time. Either of the one should be used, but not both.

• There is a DNS probe in discovery which is causing Java exceptions.
• This probe is for resolving DNS names of IPs.
• This would get triggered twice, one for SMMP Identity - Multiprobe and once again for Horizontal Pattern probe.
• When it gets triggered with SMMP Identity - Multiprobe, proper IP Addresses are being sent to DNS probe and it is processing good. No error here.
• When it gets triggered with Horizontal Pattern probe, "null" parameter is being sent instead of IP Address. And this activity seems to be redundant. 
• This is because, there are both Probes and Sensors, Patterns enabled for discovery.

Resolution

• Identify which classification is triggered for the discovery. It should be either "Standard Network Router" or "Standard Network Switch".
• Open the classifier. (Navigate to Discovery Definition -> CI Classification -> All and search for respective classifier).
• Under "Triggers Probes" section, you can remove "Horizontal Pattern".
• Re-run the discovery and it should go good now without errors.

Additional Information

You can contact Customer Support if you have any questions performing the above steps.