Firewall chains

RouterOS Beginner Basics
1

Hello,

I have a MikroTik router running RouterOS v6.49.2.
I’m confused about the firewall chains - what do they actually mean?
I’d want to see some examples of how each chain is used.

Would uploading a file apply to the output chain?
And when is the forward chain used?
And does “router’s addresses” mean an address the router has assigned to an interface?
https://wiki.mikrotik.com/wiki/Manual:IP/Firewall/Filter#Chains

Thanks

2

Check this nice diagram:

http://forum.mikrotik.com/t/firewall-vs-nat-packet-flow/135838/4

input and output are for router’s own traffic
forward is for other traffic going through router

3

Would uploading a file apply to the output chain?

Does uploading a file from your computer has as destination any address assigned to any of the Router’s Interface ? ( Input )
Does the traffic pass through the Router ? ( Forward )
Or is it originated from the router itself ? ( Output )

What do you think is the best match ?