Linux which program use port

How to find out which Port number a process is using

I want to be able to find out which port number a process is and filtering the results using a keyword. For example, I may want to quickly find out which port numbers are being used by «node» js apps. This did not work:

netstat tulnap | grep "node" 

By the way, i notice that on osx the command doesnt have a hyphen. Here are the results i got, not useful: Address Type Recv-Q Send-Q Inode Conn Refs Nextref Addr

3 Answers 3

This is how I found a solution:

 » lsof -i -P | grep node node 14489 me 12u IPv4 0x. 0t0 TCP *:4000 (LISTEN) 

Also if i knew the port and I was looking for the process name I would:

 » lsof -i :4000 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME node 14489 me 12u IPv4 0x. 0t0 TCP *:terabase (LISTEN) 

Active Internet connections (w/o servers)

Active Internet connections (only servers)

What you’re doing may also never work since GREP is never guaranteed to deliver either no, one, or more than 1 results.

But, in context of your specific case, any process IS actually unique, and has a unique number. So, you must do your search first to find a process number.

Doing a simple grep will still give you either none, one, or more than one process number. But you’ll need to find an additional filter, so that you end up with 1 process number.

If you have 1 process number, you can check port(s) being used by that process.

What makes you think «node» is reported in PS ? It may also not be.

Источник

Linux: Find Out Which Port Number a Process is Listening on

As Linux users, we sometimes need to know what port number a particular process is listening on. All ports are associated with a process ID or service in an operating system. So how do we find this port? In this article, we will present three different methods that you can use to find out which port a process is listening on.

We have run the commands and procedures described in this article on an Ubuntu 22.04 LTS system.

Method 1: Using the netstat command

Netstat, the network statistics utility, is used to display information about the network connections. This includes information about interface statistics, routing tables and much more. This utility is available on most Linux systems, so we use it to find out which ports certain processes on the system are using.

To use the netstat command, you must install the net-tools utility, if it is not already installed on your system, using the following command:

$ sudo apt install net-tools

Then run the following command:

The above command gives netstat information based on the following features:

• l: display only listening sockets
• t: display tcp connection
• n: display addresses in a numerical form
• p: display process ID/ Program name

For example, in the above output of the netstat command, Apache2 program with process ID 950 is running on port number 80.

You can also filter statistics for a specific port by incorporating the grep function into your command.

$ sudo netstat -ltnp | grep -w ':80'

This command will tell you specifically which process is running on port number 80.

Method 2: Using the lsof command

The lsof or the List of Open Files utility helps in listing all the open files on your Linux system. We can use this utility to view all processes open on a specific port.

For using the lsof command, you need to install the lsof utility if it is already not installed on your system through the following command:

Let us use lsof to view the service listening on a specific port.

This command will list all processes using TCP port number 80.

Method 3: Using the fuser command

The fuser command displays which process IDs are using the named files, sockets or file systems. We can use this command in order to view process IDs running on a specific TCP port.

For using the fuser command, you need to install the psmisc utility if it is already not installed on your system through the following command:

Let us view all the process IDs running on TCP port 3306 through the following command:

You can specify any port number in this command to view its listening processes.

In the above output, you can see that process ID 975 is listening on TCP 3306.

In order to view which program this process ID corresponds to, run the following command:

The output shows that process ID 975 corresponds to the program name MySDLd. Thus process ID 975 of the program MySQLd is listening on port number 3306.

Through the three methods you have learned in this article, you can easily view which TCP port a specific process on Linux is listening upon.

Search

About This Site

Vitux.com aims to become a Linux compendium with lots of unique and up to date tutorials.

Latest Tutorials

Источник

3 Ways to Find Out Which Process Listening on a Particular Port

A port is a logical entity that represents an endpoint of communication and is associated with a given process or service in an operating system. In previous articles, we explained how to find out the list of all open ports in Linux and how to check if remote ports are reachable using the Netcat command.

In this short guide, we will show different ways of finding the process/service listening on a particular port in Linux.

1. Using netstat Command

netstat (network statistics) command is used to display information concerning network connections, routing tables, interface stats, and beyond. It is available on all Unix-like operating systems including Linux and also on Windows OS.

In case you do not have it installed by default, use the following command to install it.

$ sudo apt-get install net-tools [On Debian/Ubuntu & Mint] $ sudo dnf install net-tools [On CentOS/RHEL/Fedora and Rocky Linux/AlmaLinux] $ pacman -S netstat-nat [On Arch Linux] $ emerge sys-apps/net-tools [On Gentoo] $ sudo dnf install net-tools [On Fedora] $ sudo zypper install net-tools [On openSUSE]

Once installed, you can use it with the grep command to find the process or service listening on a particular port in Linux as follows (specify the port).

In the above command, the flags.

• l – tells netstat to only show listening sockets.
• t – tells it to display tcp connections.
• n – instructs it to show numerical addresses.
• p – enables showing of the process ID and the process name.
• grep -w – shows matching of exact string (:80).

Note: The netstat command is deprecated and replaced by the modern ss command in Linux.

2. Using lsof Command

lsof command (List Open Files) is used to list all open files on a Linux system.

To install it on your system, type the command below.

$ sudo apt-get install lsof [On Debian, Ubuntu and Mint] $ sudo yum install lsof [On RHEL/CentOS/Fedora and Rocky Linux/AlmaLinux] $ sudo emerge -a sys-apps/lsof [On Gentoo Linux] $ sudo pacman -S lsof [On Arch Linux] $ sudo zypper install lsof [On OpenSUSE]

To find the process/service listening on a particular port, type (specify the port).

3. Using fuser Command

fuser command shows the PIDs of processes using the specified files or file systems in Linux.

You can install it as follows:

$ sudo apt-get install psmisc [On Debian, Ubuntu and Mint] $ sudo yum install psmisc [On RHEL/CentOS/Fedora and Rocky Linux/AlmaLinux] $ sudo emerge -a sys-apps/psmisc [On Gentoo Linux] $ sudo pacman -S psmisc [On Arch Linux] $ sudo zypper install psmisc [On OpenSUSE]

You can find the process/service listening on a particular port by running the command below (specify the port).

Then find the process name using PID number with the ps command like so.

$ ps -p 2053 -o comm= $ ps -p 2381 -o comm=

You can also check out these useful guides about processes in Linux.

You might also like:

That’s all! Do you know of any other ways of finding the process/service listening on a particular port in Linux, let us know via the comment form below.

Источник

Determine the process pid listening on a certain port

As the title says, I’m running multiple game servers, and every of them has the same name but different PID and the port number. I would like to match the PID of the server which is listening on certain port, and then I would like to kill this process. I need that in order to complete my bash script. Is that even possible? Because it didn’t find yet any solutions on the web.

8 Answers 8

Short version which you can pass to kill command:

This also includes processes that are connected on that port. lsof -i4TCP:80 -sTCP:LISTEN -t is probably what you want, instead.

Exactly what I was looking for. I wanted to kill a process by searching for the port it is running at.

@Nevir what do you mean by » also includes processes that are connected on that port»? Can you please explain?

The -p flag of netstat gives you PID of the process:

*use sudo if showing — instead of PID

Edit: The command that is needed to get PIDs of socket users in FreeBSD is sockstat . As we worked out during the discussion with @Cyclone, the line that does the job is:

sockstat -4 -l | grep :80 | awk '' | head -1 

netstat: 80: unknown or uninstrumented protocol used the 80 (nginx) port for testing purpoes. Not worked.

netstat -p -l | grep $PORT and lsof -i :$PORT solutions are good but I prefer fuser $PORT/tcp extension syntax to POSIX (which work for coreutils ) as with pipe:

it prints pure pid so you can drop sed magic out.

One thing that makes fuser my lover tools is ability to send signal to that process directly (this syntax is also extension to POSIX):

$ fuser -k $port/tcp # with SIGKILL $ fuser -k -15 $port/tcp # with SIGTERM $ fuser -k -TERM $port/tcp # with SIGTERM 

Источник