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

MiguelSL
Tera Contributor

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.

6 REPLIES 6

Abbas_5
Tera Sage
Tera Sage

Hello @MiguelSL,

 

Please refer to the link below:
https://www.servicenow.com/docs/bundle/washingtondc-it-operations-management/page/product/discovery/...

 

If this is helpful, please hit the thumbs up button and accept the correct solution by referring to this solution in future it will be helpful to them.

 

Thanks & Regards,

Abbas Shaik

MiguelSL
Tera Contributor

I already checked that doc but I couldn't find any information related to that specific field ("accuracy"). There are no details on how it is fetched/calculated, which might help to understand why it is coming empty.

Pratiksha
Mega Sage
Mega Sage

Accuracy is Confidence in host fingerprinting (based on port responses). 

Ok, makes sense but in that case I would imagine that the field should have a value, allowing the pattern to "make a decision" based on it. In my case, it's always coming empty and I'm testing it against quite a lot IPs. This results in the pattern being terminated for all of them and no records being inserted.