This repository contains Computer-Networks assignments including UDP pinger, Multi-threaded file downloader and implementations of Go-back-N and Stop-and-wait protocols. The last assignment is a golden code, which comprises of two parts - first one is the self implementation of nslookup, which performs name resolution for a given domain name and the second one is a DNS proxy server which supports caching as well. UDP pinger is implemented using C++ and the rest of the implementations are purely in Python.