i need your help, i would like to make audit in our Network, and i wish to do pen test on some server windows and unix or linux OS and other equipements like Cisco Router and switch

could you please help what i can do that ? i know i can use Nmap for test port and nessus for unix but is there any other tools like LANGFI ? what is the free tool can help me to do auditing for our Cisco swhtch and router ?
and anyone can let me know how i can use metsploit for get system linux or hpunix without root user ?

Best Regard & thank you advance