The default firewall rules dropping all on input at the end, so if not allowed before, nothing is allowed after.
If you write “If my memory serves me well __” it is because you have deleted the default rules, so you cannot recheck them, sinning of pride.
v6, but are like the same for v7
http://forum.mikrotik.com/t/buying-rb1100ahx4-dude-edition-questions-about-firewall/148996/4
/ip firewall filter
add chain=input action=accept connection-state=established,related,untracked comment=“defconf: accept established,related,untracked”
add chain=input action=drop connection-state=invalid comment=“defconf: drop invalid”
add chain=input action=accept protocol=icmp comment=“defconf: accept ICMP”
add chain=input action=accept dst-address=127.0.0.1 comment=“defconf: accept to local loopback (for CAPsMAN)”
add chain=input action=drop in-interface-list=!LAN comment=“defconf: drop all not coming from LAN”