Hello again 
I have a quick question relating droping of invalid packets. I found wiki entries for dropping them in the forward chain and sometimes in the input chain.
What’s the difference? Once outgoing (forward) and once incoming invalid packets?
To get the difference you need to understand what packets are going over input/forward chain.
input - processes packets going to the router itself.
forward - process packets going through the router (in other words clients traffic).
hm ok, could have looked that up, true. sorry for the trouble and thanks for the reply
Hm, I’ll add another question, since I have a weird problem with one of the routers right now.
I have a RB750 connected to a network 192.168.0.0/24 as WAN. It’s WAN IP is 192.168.0.10/24, LAN IP is 192.168.11.1/24.
If I add another IP on the WAN interface, e.g. 192.168.30.10/24, the speed of any client in 192.168.11.0/24 gets incredibly slow.
0.0.0.0/0 is routed to 192.168.0.3, which is one of the main routers with direct public internet access.
192.168.30.0/24 is just another subnet for some wireless devices. I added the IP on the WAN interface to be able to configure those directly.
Now my question is: Since I imagine wireless network causes a lot more invalid packaged than wired network (is this assumption true at all???), that this might be one of the causes of the slow WAN access from 192.168.0.10/24. With slow I mean really slow. When I do speedtests with the second WAN IP enabled, I get around 300kb. Without it, I get around 30mb.
Any ideas?