A penetration tester is conducting a port scan on a specific host.

A penetration tester is conducting a port scan on a specific host. The tester found several ports opened that were confusing in concluding the Operating System (OS) version installed. Considering the NMAP result below, which of the following is likely to be installed on the target machine by the OS?

Starting NMAP 5.21 at 2011-03-15 11:06

NMAP scan report for 172.16.40.65

Host is up (1.00s latency).

Not shown: 993 closed ports

PORT STATE SERVICE

21/tcp open ftp

23/tcp open telnet

80/tcp open http

139/tcp open netbios-ssn

515/tcp open

631/tcp open  ipp

9100/tcp open

MAC Address: 00:00:48:0D:EE:89