Splunk Search

How to use the cidrmatch() function with IPV6 IP addresses?

fdi01
Motivator

The cidrmatch() function is used to identify IP addresses that belong to a particular subnet. How do I use it with IPV6 IP addresses? Syntax?

thanks

Tags (4)
1 Solution

stephanefotso
Motivator

Hello! I Firs i suggest that you follow this doc: https://blog.icann.org/wp-content/uploads/2010/07/ipv6-address-types.pdf
Then, for example to use the cidrmatch() for 2001:0000:4136:e378:8000:63bf:3fff:fdd2 address, you can just do something like this:

........... | eval network=if(cidrmatch("2001:0000::/32",clientip), "local", "other")

which compare the IP addresses in the clientip field to a subnet range, and give the value local to the network if the value of clientip falls in the subnet range, Otherwise, network=other.

SGF

View solution in original post

stephanefotso
Motivator

Hello! I Firs i suggest that you follow this doc: https://blog.icann.org/wp-content/uploads/2010/07/ipv6-address-types.pdf
Then, for example to use the cidrmatch() for 2001:0000:4136:e378:8000:63bf:3fff:fdd2 address, you can just do something like this:

........... | eval network=if(cidrmatch("2001:0000::/32",clientip), "local", "other")

which compare the IP addresses in the clientip field to a subnet range, and give the value local to the network if the value of clientip falls in the subnet range, Otherwise, network=other.

SGF

fdi01
Motivator

thank you but does not work .
i try like that:
| eval network=if(cidrmatch("2001:0000::/32",2001:0000:4136:e378:8000:63bf:3fff:fdd2), "local", "other")
but no isue. and i have this error:
Error in 'eval' command: The expression is malformed. Expected ).

0 Karma

stephanefotso
Motivator

you don't need to test like this. My query suppose that you have a field named clientip, with IPV6 IP addresses in your events. To test with a value of clientip try this:

  your base search  | eval network=if(cidrmatch("2001:0000::/32","2001:0000:4136:e378:8000:63bf:3fff:fdd2"), "local", "other")

I think it will work

SGF

fdi01
Motivator

it work fine Mr stephanefotso is it cool

0 Karma
Get Updates on the Splunk Community!

Splunk Enterprise Security 8.x: The Essential Upgrade for Threat Detection, ...

 Prepare to elevate your security operations with the powerful upgrade to Splunk Enterprise Security 8.x! This ...

Get Early Access to AI Playbook Authoring: Apply for the Alpha Private Preview ...

Passionate about security automation? Apply now to our AI Playbook Authoring Alpha private preview ...

Reduce and Transform Your Firewall Data with Splunk Data Management

Managing high-volume firewall data has always been a challenge. Noisy events and verbose traffic logs often ...