Atomicorp

I've noticed that a number of firewall drop events for the DROP_ASL_INPUT chain are being logged where the destination port is valid and open (e.g. 443, or 80).

For example:
They tend to all be RST

TCP RST packets are used to close open TCP connections gracefully. For more information about the TCP RST read RFC 793 - Transmission Control Protocol

I was wondering if it would be possible to have a kind of a dummy's guide to why RST and potentially other packets are dropped. It might be useful for those of us who aren't TCP aficionados and see interesting things like this in the logs.