Splunk Search

Why are tstats search not filtering out local IP ranges?

dmbrcx
Explorer

Hi,

I am using tstats to search the Network Datamodel for outbound SMB traffic (port 445) to external IP address ranges.

Why are local IP ranges still appearing in my search results?

Here is my syntax:

 

 

| tstats summariesonly=t fillnull_value="MISSING" count from datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port="445" AND NOT All_Traffic.dest IN ("10.0.0.0/8","172.16.0.0/16","192.168.0.0/24") earliest=-15m latest=now
by _time, All_Traffic.dest, All_Traffic.dest_port,All_Traffic.src, All_Traffic.src_port, All_Traffic.action, All_Traffic.bytes, index, sourcetype

 

 

Screenshot:

Splunk Forum Question 2023-03-15_15-01.png

I believe I have filtered them correctly, but hmm...

Labels (1)
0 Karma
1 Solution

yuanliu
SplunkTrust
SplunkTrust

Two things.  First, CIDR match doesn't go with the IN operator.  You have to specify them individually, like

| tstats summariesonly=t fillnull_value="MISSING" count from datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port="445"
 AND NOT (All_Traffic.dest="10.0.0.0/8" OR All_Traffic.dest="172.16.0.0/16" OR All_Traffic.dest="192.168.0.0/24")
 earliest=-15m latest=now
by _time, All_Traffic.dest, All_Traffic.dest_port,All_Traffic.src, All_Traffic.src_port, All_Traffic.action, All_Traffic.bytes, index, sourcetype

Second, beware of Limitations of CIDR matching with tstats.

View solution in original post

dmbrcx
Explorer

Thank you. Those limitations are interesting. I am surprised I have not noticed this issue before.

0 Karma

yuanliu
SplunkTrust
SplunkTrust

Two things.  First, CIDR match doesn't go with the IN operator.  You have to specify them individually, like

| tstats summariesonly=t fillnull_value="MISSING" count from datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port="445"
 AND NOT (All_Traffic.dest="10.0.0.0/8" OR All_Traffic.dest="172.16.0.0/16" OR All_Traffic.dest="192.168.0.0/24")
 earliest=-15m latest=now
by _time, All_Traffic.dest, All_Traffic.dest_port,All_Traffic.src, All_Traffic.src_port, All_Traffic.action, All_Traffic.bytes, index, sourcetype

Second, beware of Limitations of CIDR matching with tstats.

Get Updates on the Splunk Community!

Index This | I am a number, but when you add ‘G’ to me, I go away. What number am I?

March 2024 Edition Hayyy Splunk Education Enthusiasts and the Eternally Curious!  We’re back with another ...

What’s New in Splunk App for PCI Compliance 5.3.1?

The Splunk App for PCI Compliance allows customers to extend the power of their existing Splunk solution with ...

Extending Observability Content to Splunk Cloud

Register to join us !   In this Extending Observability Content to Splunk Cloud Tech Talk, you'll see how to ...