Block all, allow some Firewall

RouterOS General
1

Hi All

Recently did my first Mikrotik course, so well on my way to global domination :sweat_smile: … but first some random stupid questions …

How would you configure a firewall to block everything coming in and only configuring certain things to pass through? Is it literally just the rules in the firewall or do you have to enable something?

Thanks,
R

2

It is literally just the rules. Check the default filter rules of the hXX products, it is almost that if you replace the “leaky drop” rule at the end of each chain (input and forward) by a complete drop. Or check this.

3

Awesome, thanks, looks like good start.

The “logics” part of my brain is wanting to ask, where in relation to the interfaces does the firewall reside? As in how far does the data go before the firewall decides to drop it for instance.

Thanks,
R

4

The first place to eventually drop packets you don’t like is the raw table, normally you do most of the job in the filter table. Rules in both can refer to in-interface (i. e. at most one interface per rule can be matched) or to in-interface-list (which matches if the actual input interface of the packet is any of those on the list). This set of drawings shows the packet travel through the machine and the positions of individual firewall tables on that path.