When i make ip scan in winbox i see 1.0.0.0/8 addresses which are strange and referring to some company called totbb in thailand,these addresses make trouble for me by making huge traffic between me and the clients,i tried firewall filter with no result.its stuck somehow in clients routers or devices,i don`t know really what is going on!!!also they refer to strange dns.
Check your network may be someone has connected his router to your network that is already using internet from another source also try to get the IP on your own system if its Broadcasting DHCP and try to check the gateway.
Regards,
Romahiz romahiz.wordpress.com