Are there any other distinctions between Ports and Towns? Can anyone Visit or Attack a Port as if it were a Town? As I recall, the rules on Attack refer to "Towns" and never mention Ports, yet the Home Ports have a Red "12" Attack Value.
You can attack ports, just like any other red-banner town (12 + 2 = 14 defense). In fact, there's a building that gives a large VP bonus for taking over a port.