Mikrotik is a router os that comes with a lot of features.  To see what you can do with it, just visit their official website www.mikrotik.com.  I prefer using mikrotik as an alternative to cisco products because it is cheaper, easy to configure and the community is growing bigger.  But for free versions I would use PFSense or mOnOwall whose bare-bones are derived from BSD. One of the problems in a network are bogus IPs or also known as bogon.