How do I close an open port from the terminal on the Mac

Question

I opened port  5955 from a java class to comunicate from a client  How do i close this port after I am done  and also which command can show me if port open or closed

User · Answer

In 2018 here is what worked for me using MacOS HighSierra  sudo lsof -nPi  yourPortNumber then  sudo kill -9 yourPIDnumber

User · Answer

First find out the Procees id  pid  which has occupied the required port  e g 5434   ps aux   grep 5434   2 kill that process     kill -9  lt pid gt

User · Answer

You can also use this first command to kill a process that owns a particular port  sudo netstat -ap   grep   lt port number gt   For example  say this process holds port 8000 TCP  then running the command  sudo netstat -ap   grep  8000  will output the line corresponding to the process holding port 8000  for example  tcp  0  0   8000       LISTEN  4683 procHoldingPort  In this case  procHoldingPort is the name of the process that opened the port  4683 is its pid  and 8000  note that it is TCP  is the port number it holds  which you wish to close   Then kill the process  following the above example  kill  4683  As others mentioned here out  if that doesn t work  you can try using kill with -9 as an argument   kill -9 4683  Again  in general  it s better to avoid sending SIGKILL  -9  if you can

User · Answer

try below  assuming running port is 8000   free-port     kill    lsof -t -i  8000        I found the reference here

User · Answer

One liner is best  kill -9   lsof -i PORT -t  2 gt   dev null   Example   On mac  wanted to clear port 9604  Following command worked like a charm   kill -9   lsof -i 9604 -t  2 gt   dev null

User · Answer

very simple find port 5900    sudo lsof -i  5900   then considering 59553 as PID  sudo kill 59553

User · Answer

I use lsof combined with kill  as mentioned above  but wrote a quick little bash script to automate this process   With this script  you can simply type killport 3000 from anywhere  and it will kill all processes running on port 3000   https   github com xtrasimplicity killport

User · Answer

However you opened the port  you close it in the same way  For example  if you created a socket  bound it to port 0 0 0 0 5955  and called listen  close that same socket   You can also just kill the process that has the port open   If you want to find out what process has a port open  try this   lsof -i  5955   If you want to know whether a port is open  you can do the same lsof command  if any process has it open  it s open  otherwise  it s not   or you can just try to connect to it  e g    nc localhost 5955   If it returns immediately with no output  the port isn t open   It may be worth mentioning that  technically speaking  it s not a port that s open  but a host port combination  For example  if you re plugged into a LAN as 10 0 1 2  you could bind a socket to 127 0 0 1 5955  or 10 0 1 2 5955  without either one affecting the other  or you could bind to 0 0 0 0 5955 to handle both at once  You can see all of your computer s IPv4 and IPv6 addresses with the ifconfig command

User · Answer

When the program that opened the port exits  the port will be closed automatically  If you kill the Java process running this server  that should do it

User · Answer

I have created a function for this purpose   function free port         if   -z  1        then         echo no Port given     else         PORT  1          PID   sudo lsof -i   PORT    store the PID  that is using this port           if   -z  PID            then             echo port   PORT is already free          else             sudo kill -9  PID   kill the process  which frees the port             echo port   PORT is now free          fi     fi    free port 80   you need to change this port number   Copy  amp  pasting this block of code in your terminal should free your desired port  Just remember to change the port number in last line

User · Answer

To find the process try   sudo lsof -i  portNumber   Kill the process which is currently using the port using its PID  kill PID   and then check to see if the port closed  If not  try   kill -9 PID   I would only do the following if the previous didnt work  sudo kill -9 PID   Just to be safe  Again depending on how you opened the port  this may not matter

User · Answer

Find out the process ID  PID  which is occupying the port number  e g   5955  you would like to free  sudo lsof -i  5955  Kill the process which is currently using the port using its PID  sudo kill -9 PID

[macos] How do I close an open port from the terminal on the Mac?

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