So. If you want to use squid 3.2.8 or 3.3.2 as a transparent proxy, in a network as above, then there are some things that should be changed, the configuration on the router mikrotik and the Squid.
A few steps below, would be similar to the steps at "Transparent Proxy Server, Squid 3.3.2 / 3.2.8 on Ubuntu 12.10 + Shorewall"
We begin by configuring the Ethernet.
vi /etc/network/interfaces