Firewall filter effecting nated public IP?

RouterOS General
1

I have filters that block 25 to my input chain.

If I have a public ip dst-nated to an internal private ip, does to filter to my input effect that traffic?

ie

On my router:

/ip address
add address=x.x.x.x/24 comment=“Public IP - for cust” interface=WAN
add address=y.y.y.1/30 comment=“Private IP for cust” interface=LAN1

/ip firewall nat
add action=dst-nat chain=dstnat comment=“Nat pub to priv” dst-address=x.x.x.x to-addresses=y.y.y.2
add action=src-nat chain=srcnat comment=“Nat priv to Pub” out-interface=WAN src-address=y.y.y.2 to-addresses=x.x.x.x

/ip firewall filter
add action=drop chain=input comment=“block port 25” dst-port=25 protocol=tcp

2

Look at this to understand the packet flow in RouterOS.

http://wiki.mikrotik.com/wiki/Manual:Packet_Flow

3

No. The input chain affects traffic to the router. The traffic you describe will be affected by the forward chain and the DST NAT occurs before the forward chain is entered.