I'm a splunk beginner, and have been able to do all kinds of interesting things with my logs that are structured as attribute=value pairs. The attribute names are discovered and I can graph the top 10 occurrences, etc.
What I'm having a harder time with is my logs that do not have attribute names built in. For example, my DHCP logs, I want to analyze IP address assignments, unusual MAC addresses, hostname to MAC or IP, etc. I've had some success with 'rex' on other logs, but not with these. Is rex the best/easiest way? Other suggestions for learning the fields I want?