During a penetration test from the Internet, Jane, the system administrator, was able to establish a
connection to an internal router, but not successfully log in to it. Which ports and protocols are MOST
likely to be open on the firewall? (Select FOUR).
A.
21
B.
22
C.
23
D.
69
E.
3389
F.
SSH
G.
Terminal services
H.
Rlogin
I.
Rsync
J.
Telnet
Explanation:
The question states that Jane was able to establish a connection to an internal router. Typical ports and
protocols used to connect to a router include the following:
B, F: Port 22 which is used by SSH (Secure Shell).
C, J: Port 23 which is used by Telnet.
SSH and Telnet both provide command line interfaces for administering network devices such as routers
and switches.
Incorrect Answers:
A: Port 21 is used by FTP (File Transfer Protocol). It is used for downloading and uploading files over a
network using a TCP connection. It is not used for connecting to network devices such as routers or
switches.
D: Port 69 is used by TFTP (Trivial File Transfer Protocol). It is used for downloading and uploading files
over a network using a UDP connection. It is not used for connecting to network devices such as routers
or switches.
E: Port 3389 is used by Remote Desktop Protocol (RDP). RDP is used for connecting to Windows
computers. It is not used for connecting to network devices such as routers or switches.
G: Terminal Services is an earlier name for Remote Desktop Services. Terminal Services uses Remote
Desktop Protocol (RDP) on port 3389. It is not used for connecting to network devices such as routers or
switches.
H: Rlogin (Remote Login) uses port 513 and is used for connecting to Linux or Unix computers. It is not
used for connecting to network devices such as routers or switches.
I: RSync is a file synchronization protocol that uses port 873. It is used for synchronizing files between
Linux or Unix computers. It is not used for connecting to network devices such as routers or switches.
http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers