MacNetCalc is an IP network/subnet calculator written in Python using the PyObjC bridge and the Cocoa UI. Visually similar to Boson's 'Subnetit'.
Follow MacNetCalc - IP Calculator for OS X
Server and Application Monitor helps you discover application dependencies to help identify relationships between application servers. Drill into those connections to view the associated network performance such as latency and packet loss, and application process resource utilization metrics such as CPU and memory usage. Determine if process utilization or network performance is affecting the application and end-user performance.