Если о скорректировать ответ роутера:
reject-with
(icmp-admin-prohibited | icmp-net-prohibited | icmp-protocol-unreachable | icmp-host-prohibited | icmp-network-unreachable | tcp-reset | icmp-host-unreachable | icmp-port-unreachable; Default: icmp-network-unreachable)
https://wiki.mikrotik.com/wiki/Manual:IP/Firewall/...