http://arav.i2p/stuff/article/hardening_mikrotik
I put a value from drop-down list named none dynamic , so router could decide by itself, and I found, that in a terminal, this actually means 1h. In a terminal: > ip/firewall/filter/add place-before=<last rule number> chain=input action=add-src-to-address-list protocol=tcp psd=21,3s,3,1 address-list=whores address-list-timeout=1h in-interface-list=WAN .