Splunk Subsearch CSV: A Step-by-Step Guide

When working with Splunk, you may encounter situations where you need to use a subsearch to retrieve data from a CSV file. In this article, we will walk you through the process of setting up a subsearch using a CSV file in Splunk.

Preparing Your CSV File

Before you can start setting up your subsearch, you need to prepare your CSV file. This involves making sure that all entries are in CIDR format and that there is a comma between the first and second columns.

Here's what I used as my lookup file after making these changes:

IP,Application

Once you have made the necessary corrections, click the Browse button and select the CSV file.

Setting Up Your Subsearch

Now it's time to set up your subsearch within Splunk. To do this, follow these steps:

1. Log into Splunk and click Settings -> Lookups in the upper right.

2. Click Add new next to Lookup table files.

3. Change the Destination app drop-down menu to match whatever app you're using in your environment for this search.

Simulating Search Results

Next, you need to simulate some search results. This can be done by running a search that returns data from your CSV file. I used the following SPL to generate some random IP addresses in my results:

`comment('Mocked-up sample data with credit to to4kawa')`

You don't need to do this if you're getting IP addresses in the real searches you're using in your environment.

Sorting Your List

Once you have simulated some search results, you can sort your list from most-specific to least-specific. This means changing specific IP addresses like 192.168.2.5 to 192.168.2.5/32 instead.

By following these steps, you should be able to set up a subsearch using a CSV file in Splunk. Remember that performance may be affected if your lookup CSV file has a large number of values and you have a lot of results in your search to lookup.

In this article, we have covered the process of setting up a subsearch using a CSV file in Splunk. With these steps, you should be able to retrieve data from a CSV file and use it to inform your searches within Splunk.

Splunk subsearch csv