Re-write host field for Splunk

Hello, this is probably simple, but I can’t get it to work. I just want to remove IPV6 encapsulation from the host field of events arriving at Cribl via syslog. So, existing host field is ::ffff:10.1.1.1, I want it to be just 10.1.1.1. For some reason I can’t get this to work, Splunk shows a null value for host when I try to EVAL, MASK, REGEX, etc. Anyone have a way to do this?

1 UpGoat

Here is how I was able to do it. In my example, I have host set to your example above:

image

Then I use the Regex Extract function to extract out the ipv4 address from host:
Regex is ^(?:[^\d]+)(?<host_regex>.+)$

Then I use an Eval function to replace the host value with the host_regex value and then remove the host_regex field.

1 UpGoat