Testing port connectivity Flashcards
how would I test connectivity on windows
Test-NetConnection
How would I test port connectivity on Linux and mac
netcat
What tool can we run through the command nc, and has two mandatory arguments, a host and a port?
Netcat
What happens if you run:
nc google.com 80
it will try to establish a connection on port 80 to google.com.
What happens if the nc connection fails?
the command will exit
What happens if the nc command succeeds?
you see a blinking cursor waiting for more input.
This is a way for you to actually send application layer dat to the listening service from your own keyboard.
the blinking cursor after an nc command succeeds.
What command can I issue if I’m only curious about the status of a port?
nc with the -z flag
what does the -z flag stand for in nc?
zero input output mode
what does the -v flag stand for?
verbose. Makes the command output useful to human eyes as opposed to non-verbose.
what output type is best for usage and scripts?
non-verbose.
What happens if I issue:
nc -z -v google.com 80
Connection to google.com 80 port [tcp/http] succeeded!
The command’s output will simply tell me if a connection to the port in question is possible or not.
Test-NetConnection google.com
running test connection with only the host specified
It will default to using an ICMP echo request, like Ping does, but displays more data.
What commmand result default displays data including the data link layer protocol being used, computer name, remote address, interface alias, sourceaddress, pingSucceeded, PingReplyDetails
Test-NetConnection
How can I ask Test-NetConnection to test connectivity to a specific port?
Test-NetConnection -port
what are tools used to test network connectivity and communication between devices?
Netcat (nc) for Linux and Macand Test-NetConnection for Windows
What tools check port connectivity at the transport layer, which creates and manages communications in a network through connections?
Netcat and Test-NetConnection
what stands for networking?
net
what stands for concatenate, from unix?
cat
what means to link things together in a chain or series?
concatenate, cat
What command tries to establish a transmission control protocol connection to the host <google.com> on the port <port 80>?</google.com>
nc [options] <host> <port>
ex: nc google.com 80</port></host>
in netcat, what can the host be?
a website or targeted IP address
In netcat, what can the port be?
a specific port or range of port numbers
what command tells netcat to open a user datagram protocol (udp) connection, instead of a TCP connection?
nc -u <host> <port></port></host>
Why what I need to use UDP ?
speed or efficiency purposes
what command stands for zero input/ output and tells netcat to scan for open ports?
nc -z <host> <port></port></host>
what netcat flag what I used to scan for unneeded services that could be listening into a network without sending any data to them? This can be combined with using a range of port numbers instead of a single port
nc -z <host> <port></port></host>
what netcat command stands for verbose and gives extended output text important for debugging and troubleshooting
nc -v <host> <port></port></host>
what command would I run if I want a scan looking for listening devices that will return lists of port and statuses on the network or website being scanned?
nc -v <host> <port></port></host>
what stands for very verbose and gives more output text than just verbose
nc -vv <host> <port></port></host>
what would I use if I’ve asked for a very detailed report of all ports and their statuses within the company network to get robust information on all ports and their statuses
nc -vv <host> <port></port></host>
refers to a local port for a connection. Some protocols require specific source port to work properly, this lets you specify what port to connect from
nc -p <localport> <host> <port></port></host></localport>
executes a program after connection established. this option is not supported by all versions of netcat, but you can also use standard unix command line pipelines to pass network input two or from other programs
nc -e <program> <host> <port></port></host></program>
prevents domain name server lookup. use this when you have an IP address and numeric port to use for the connection and you want to avoid the overhead of domain name server, DNS, or if it is not working properly
nc -n <addr> <port></port></addr>
if I want to evaluate a network for open doors a weak connections that would allow someone to hack into the network what can I run to determine if a connection to the port 80 is possible to google?
nc -v -z google.com 80
command test paying connectivity and displays diagnostic information for a connection from the host on the selected port
Test-NetConnection <host> <port></port></host>
what command, used in powershell, is case sensitive?
Test-NetConnection
we command will I use of data transfer on the network is moving very slowly so I want to check the quality of the connection and view details about it?
Test-NetConnection -InformationLevel “Detailed”
Tests ping connectivity with detailed results
Test-NetConnection -InformationLevel “Detailed”
Tests a connection to a remote host
Test-NetConnection -ComputerName [remote host]
Tests TCP connectivity to a specific host in port. This can be combined with the display detailed results option
example: PS C:> Test-NetConnection -ComputerName www.google.com
-Port 80 -InformationLevel Detailed
Test-NetConnection -ComputerName [remote host] -Port [port
number]
Performs root diagnostics to connect to a remote host. This can require administrator privileges so you may have to run your powershell window as administrator
Test-NetConnection -ComputerName [remote host]
-DiagnoseRouting
Performs root diagnostics to connect or remote hosts with routing constraints. example: an employees having trouble connecting to a specific website from their computer, but other sites are loading fine. I can track connecting to the site directly with this:
Test-NetConnection -ComputerName www.example.com -Port 80
-InformationLevel Detailed
Test-NetConnection -ComputerName [remote host]
-constrainInterface [interface number] -DiagnoseRouting
-InformationLevel “Detailed”
