Credential-less Discovery: "accuracy" field coming from nmap

[MiguelSL]

Hello everyone,

We are currently testing Credential-less Discovery and while debugging the pattern to understand how it works, I noticed the following:

The first thing that the pattern is doing is to scan ports in the host and the response is stored in a variable/table called '$HostDiscovery'. One of the variables inside '$HostDiscovery' is called "accuracy", which is used in subsequent steps as a condition and even in some scripts; if this field ('accuracy') comes empty for all the ports of a host, then the pattern execution is terminated, preventing the creation of the record in CMDB.

The issue is that this is happening with a lot of IPs, stopping the creation of a lot of records. What I'd like to understand is the nature of the "accuracy" field; what does it represent? what would be the consequences of bypassing it during the pattern execution?

I'm assuming it represents something similar to a score, but I don't know why its' coming empty in so many cases or what's its purpose.

This KB explains what I'm seeing, but I don't have the issue described in the KB (which is that the conditions are failing): https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB1638846

Thanks a lot in advance! Any guidance will be greatly appreciated since I haven't been able to find much information about this. I'm attaching a couple of images for your reference.

[Pratiksha]

Can you check if the ports are open on the device. Start with only one device and check for outcome. 

[MiguelSL]

Some are (80, 443 & 22). Here is the Shazzam response for an IP I took as an example:

<scanner name="BannerTCP" port="902" portprobe="esxi" protocol="tcp" result="refused" service="ESXi"/>
<scanner name="NBT" port="137" portprobe="wins" protocol="udp" result="unresolved" service="ms-nb-ns"/>
<scanner name="GenericTCP" port="135" portprobe="wmi" protocol="tcp" result="refused" service="epmap"/>
<scanner name="DNS" port="53" portprobe="dns" protocol="udp" result="unresolved" service="dns"/>
<scanner name="HTTP" port="80" portprobe="http" protocol="tcp" result="open" service="http"></scanner>
<scanner name="HTTP" port="443" portprobe="http" protocol="tcp" result="open" service="https"/>
<scanner name="SLP" port="427" portprobe="slp" protocol="udp" result="timed_out" service="slp"/>
<scanner name="BannerTCP" port="22" portprobe="ssh" protocol="tcp" result="open" service="ssh"></scanner>
<scanner name="BannerTCP" port="5480" portprobe="vmapp" protocol="tcp" result="refused" service="vmapp_https"/>
<scanner name="GenericTCP" port="5989" portprobe="wbem" protocol="tcp" result="refused" service="wbem_https"/>
<scanner name="HTTPS" port="5986" portprobe="winrm_ssl" protocol="tcp" result="timed_out" service="winrm_ssl"/>
<scanner name="BannerTCP" port="9443" portprobe="vmapp" protocol="tcp" result="refused" service="vmapp6_https"/>