I just installed this (Elastic-6 with included Logstash and Kibana) and I've been playing around with data from my DHCP server.

I'm able to send a csv (powershell created) using filebeat and parsing with logstash csv filter with no problems... I also discovered the data defaults to strings... using csv convert fixed that and all is great!

Now comes the question:
I want to have one of the fields "ScopeID" be an actual IP and not a number. I do not see this as something convert can do. So searching this website and others, seems the answer is to create a new Template.. OK.. WHY?

What is the difference between a new template and doing the conversion with mutate or convert? I haven't  found any info on why/when one needs to create a new template and not leverage mutate or convert.

Not asking how to do it ;-) .. I just want to understand the why.