Splunk Search

Comparing IP Addresses for differences

swright_rl
Explorer

Hi All,

I'm trying to create a search, to potentially be made into a monitoring rule later on.

What I am trying to achieve is a way to compare if a user has logged into his machine from a wildly different IP address.  This will be using external IP addresses only.

As an example I want to know if a user logged into the estate from an IP which wasn't the same or similar as the previous day.

 

UserTodayYesterday
User A155.123.1.1155.123.1.1
User B155.124.1.2155.125.20.2
User C155.166.2.522.18.254.56

 

In the table able, I have 3 users, user A and B have logged into pretty similar IP's although user B has logged in from a different one today ( this often happens in our logs ).  What I am more wanting to see is User C, who has logged into from a completely subnet IP and is not similar to their IP from the previous day. 

This is what I have so far:

 

index=foo (earliest=-1d@d latest=now())  
| eval TempClientIP=split(ForwardedClientIpAddress,",")
| eval ClientIP=mvindex(TempClientIP,0) 
|  eval ClientIP1=mvindex(TempClientIP,1) 
|  eval ClientIP2=mvindex(TempClientIP,2) 
| search NOT ClientIP=10.*
| where LIKE("ClientIP","ClientIP")
| eval when=if(_time<=relative_time(now(), "@d"), "Yesterday", "Today")
| chart values(ClientIP) over user by when 
|  where Yesterday!=Today

 

 

Some context regarding the search the ForwardedClientIpAddress field has 3 items inside, ClientIP + ClientIP1 are the same address, ClientIP2 is the end internal address. ClientIP can be an internal address, which is why there is a NOT to remove it from the searches.

 

Any help would be very much appreciated. 

 

Thanks

Labels (1)
Tags (3)
0 Karma
Get Updates on the Splunk Community!

Index This | What is broken 80% of the time by February?

December 2025 Edition   Hayyy Splunk Education Enthusiasts and the Eternally Curious!    We’re back with this ...

Unlock Faster Time-to-Value on Edge and Ingest Processor with New SPL2 Pipeline ...

Hello Splunk Community,   We're thrilled to share an exciting update that will help you manage your data more ...

Splunk MCP & Agentic AI: Machine Data Without Limits

Discover how the Splunk Model Context Protocol (MCP) Server can revolutionize the way your organization uses ...