Command Line for Looking at Specific Port

Here is the easy solution of port finding...

In cmd:

netstat -na | find "8080"

In bash:

netstat -na | grep "8080"

In PowerShell:

netstat -na | Select-String "8080"

You can use the netstat combined with the -np flags and a pipe to the find or findstr commands.

Basic Usage is as such:

netstat -np <protocol> | find "port #"

So for example to check port 80 on TCP, you can do this: netstat -np TCP | find "80" Which ends up giving the following kind of output:

TCP    192.168.0.105:50466    64.34.119.101:80       ESTABLISHED
TCP    192.168.0.105:50496    64.34.119.101:80       ESTABLISHED

As you can see, this only shows the connections on port 80 for the TCP protocol.

I use:

netstat –aon | find "<port number>"

here o represents process ID. now you can do whatever with the process ID. To terminate the process, for e.g., use:

taskkill /F /pid <process ID>

when I have problem with WAMP apache , I use this code for find which program is using port 80.

netstat -o -n -a | findstr 0.0:80

3068 is PID, so I can find it from task manager and stop that process.

As noted elsewhere: use netstat, with appropriate switches, and then filter the results with find[str]

Most basic:

netstat -an | find ":N"

or

netstat -a -n | find ":N"

To find a foreign port you could use:

netstat -an | findstr ":N[^:]*$"

To find a local port you might use:

netstat -an | findstr ":N.*:[^:]*$"

Where N is the port number you are interested in.

-n ensures all ports will be numerical, i.e. not returned as translated to service names.

-a will ensure you search all connections (TCP, UDP, listening...)

In the find string you must include the colon, as the port qualifier, otherwise the number may match either local or foreign addresses.

You can further narrow narrow the search using other netstat switches as necessary...

Further reading (^0^)

netstat /?

find /?

findstr /?

netstat -a -n | find /c "10.240.199.9:8080"

it will give you number of sockets active on a specific IP and port(Server port number)

For Windows 8 User : Open Command Prompt, type netstat -an | find "your port number" , enter .

If reply comes like LISTENING then the port is in use, else it is free .

To improve upon @EndUzr's response:

To find a foreign port (IPv4 or IPv6) you can use:

netstat -an | findstr /r /c:":N [^:]*$"

To find a local port (IPv4 or IPv6) you can use:

netstat -an | findstr /r /c:":N *[^ ]*:[^ ]* "

Where N is the port number you are interested in. The "/r" switch tells it to process it as regexp. The "/c" switch allows findstr to include spaces within search strings instead of treating a space as a search string delimiter. This added space prevents longer ports being mistreated - for example, ":80" vs ":8080" and other port munging issues.

To list remote connections to the local RDP server, for example:

netstat -an | findstr /r /c:":3389 *[^ ]*:[^ ]*"

Or to see who is touching your DNS:

netstat -an | findstr /r /c:":53 *[^ ]*:[^ ]*"

If you want to exclude local-only ports you can use a series of exceptions with "/v" and escape characters with a backslash:

netstat -an | findstr /v "0.0.0.0 127.0.0.1 \[::\] \[::1\] \*\:\*" | findstr /r /c:":80 *[^ ]*:[^ ]*"

This will help you

netstat -atn | grep <port no>          # For tcp
netstat -aun | grep <port no>           # For udp
netstat -atun | grep <port no>          # For both

It will give you all active sockets on a specific IP:

netstat -an | find "172.20.1.166"

For port 80, the command would be : netstat -an | find "80" For port n, the command would be : netstat -an | find "n"

Here, netstat is the instruction to your machine

-a : Displays all connections and listening ports -n : Displays all address and instructions in numerical format (This is required because output from -a can contain machine names)

Then, a find command to "Pattern Match" the output of previous command.

In RHEL 7, I use this command to filter several ports in LISTEN State:

sudo netstat -tulpn | grep LISTEN | egrep '(8080 |8082 |8083 | etc )'

in linux： To find a foreign port you could use:

netstat -anp |grep port|awk '{ print $5 }' |grep port

To find a local port you might use:

netstat -anp |grep port|awk '{ print $4 }' |grep port