Splunk Search

How does one search for a CIDR range of addresses?

samalchow
Observer

If I want to search for a range of addresses, say anything in 10.0.1.0/24 from anywhere in the log, how do you do that? I can't find anything that works.

Tags (1)
0 Karma

lball
Explorer

You can frame the search with wild cards. Example: src_ip=10.1.2.[wcrd] for a /24 CIDR range or src_ip=10.7.[wcrd].[wcrd] for a /16 CIDR range, etc.

[wcrd] = *

(I was having trouble getting the * to show when using more than 1 in the IP addresses.)

dfrankekcg
Explorer

If the IP ranges are consecutive you can use an online CIDR calculator to get the CIDR notation to use. Example: to search where src_ip is between 127.0.120.0 and 127.0.122.0, use src_ip=127.0.120.0/23

Ayn
Legend

You can't do CIDR defined search on freetext. You can however do it if you have the IP addresses you want to match against in extracted fields. In other words,

10.0.0.0/24

won't work, but

src_ip=10.0.0.0/24

will.

Get Updates on the Splunk Community!

Accelerating Observability as Code with the Splunk AI Assistant

We’ve seen in previous posts what Observability as Code (OaC) is and how it’s now essential for managing ...

Integrating Splunk Search API and Quarto to Create Reproducible Investigation ...

 Splunk is More Than Just the Web Console For Digital Forensics and Incident Response (DFIR) practitioners, ...

Congratulations to the 2025-2026 SplunkTrust!

Hello, Splunk Community! We are beyond thrilled to announce our newest group of SplunkTrust members!  The ...