Linux: What Process is Listening on Port? Find Out Now!
Are you curious about which process is listening on a specific port in your Linux system? Knowing the process responsible for a particular port can be crucial for troubleshooting network issues or identifying potential security risks. In this article, we will explore various methods to find out which process is listening on a port in Linux. Whether you prefer using command-line tools like netstat, ss, lsof, fuser, or sockstat, we’ve got you covered. By the end of this article, you will have a comprehensive understanding of how to identify the process associated with a specific port in Linux.
Introduction
In Linux, a process can listen on a specific port to accept incoming network connections. This allows the process to communicate with other processes or devices over the network. However, it can sometimes be challenging to determine which process is responsible for a particular port, especially in complex network environments.
Fortunately, Linux provides several command-line tools that can help us identify the process listening on a specific port. These tools include netstat, ss, lsof, fuser, and sockstat. Each tool has its own syntax and options, but they all serve the same purpose: to provide information about network connections and the processes associated with them.
In the following sections, we will explore each method in detail, explaining how to use the command-line tools to find the process listening on a port. Let’s dive in!
Method 1: Using the netstat command with the -tuln option
The netstat command is a versatile tool for displaying network-related information in Linux. By using the -tuln option, we can filter the output to only show TCP and UDP listening ports. Here’s how you can use the netstat command to find the process listening on a specific port:
netstat -tuln | grep <port>Replace <port> with the desired port number. The command will display the process ID (PID) and the process name associated with the specified port.
For example, to find the process listening on port 80, you would run:
netstat -tuln | grep 80The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 2: Using the ss command with the -tuln option
The ss command is another powerful tool for displaying network socket information in Linux. Similar to netstat, we can use the -tuln option to filter the output and show TCP and UDP listening ports. Here’s how you can use the ss command to find the process listening on a specific port:
ss -tuln | grep <port>Replace <port> with the desired port number. The command will display the process ID (PID) and the process name associated with the specified port.
For example, to find the process listening on port 22, you would run:
ss -tuln | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 3: Using the lsof command with the -i option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i option, we can filter the output to only show network-related information. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i :<port>Replace <port> with the desired port number. The command will display the process ID (PID) and the process name associated with the specified port.
For example, to find the process listening on port 443, you would run:
lsof -i :443The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 4: Using the fuser command with the -n option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n option, we can specify the protocol (tcp or udp) and the port number. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n <protocol> <port>/<port>Replace <protocol> with either tcp or udp, and <port> with the desired port number. The command will display the process ID (PID) and the process name associated with the specified port.
For example, to find the process listening on port 3306 using the tcp protocol, you would run:
fuser -n tcp 3306The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 5: Using the sockstat command
The sockstat command is a lesser-known tool for displaying network socket information in FreeBSD and some Linux distributions. It provides a concise output that includes the process ID (PID) and the process name associated with each socket. Here’s how you can use the sockstat command to find the process listening on a specific port:
sockstat -l | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 8080, you would run:
sockstat -l | grep 8080The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 6: Using the nestat command with the -p option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -p option, we can show the process ID (PID) and the process name associated with each network connection. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -p | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53, you would run:
nestat -p | grep 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 7: Using the lsof command with the -i :port option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i :port option, we can filter the output to only show network-related information for a specific port. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i :<port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 8080, you would run:
lsof -i :8080The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 8: Using the fuser command with the -n tcp port option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp port option, we can specify the TCP protocol and the port number. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22 using the TCP protocol, you would run:
fuser -n tcp 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 9: Using the ss command with the -p option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -p option, we can show the process ID (PID) and the process name associated with each network connection. Here’s how you can use the ss command to find the process listening on a specific port:
ss -p | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 443, you would run:
ss -p | grep 443The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 10: Using the nestat command with the -l option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -l option, we can show only listening sockets. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -l | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 80, you would run:
nestat -l | grep 80The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 11: Using the lsof command with the -i tcp:port option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i tcp:port option, we can filter the output to only show TCP network-related information for a specific port. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i tcp:<port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22 using the TCP protocol, you would run:
lsof -i tcp:22The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 12: Using the fuser command with the -n udp port option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n udp port option, we can specify the UDP protocol and the port number. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n udp <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
fuser -n udp 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 13: Using the ss command with the -l option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -l option, we can show only listening sockets. Here’s how you can use the ss command to find the process listening on a specific port:
ss -l | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 8080, you would run:
ss -l | grep 8080The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 14: Using the nestat command with the -t option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -t option, we can show only TCP connections and listening sockets. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -t | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22 using the TCP protocol, you would run:
nestat -t | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 15: Using the lsof command with the -i udp:port option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i udp:port option, we can filter the output to only show UDP network-related information for a specific port. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i udp:<port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
lsof -i udp:53The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 16: Using the fuser command with the -n tcp/udp port option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port option, we can specify both the TCP and UDP protocols and the port number. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 17: Using the ss command with the -t option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -t option, we can show only TCP connections and listening sockets. Here’s how you can use the ss command to find the process listening on a specific port:
ss -t | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22 using the TCP protocol, you would run:
ss -t | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 18: Using the nestat command with the -u option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -u option, we can show only UDP connections and listening sockets. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -u | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
nestat -u | grep 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 19: Using the lsof command with the -i tcp:port -sTCP:LISTEN option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i tcp:port -sTCP:LISTEN option, we can filter the output to only show TCP network-related information for a specific port in the LISTEN state. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i tcp:<port> -sTCP:LISTENReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified port in the LISTEN state.
For example, to find the process listening on port 80 using the TCP protocol, you would run:
lsof -i tcp:80 -sTCP:LISTENThe output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 20: Using the fuser command with the -n tcp/udp port/tcp/udp option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp option, we can specify both the TCP and UDP protocols and the port number. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified ports.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 21: Using the ss command with the -u option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -u option, we can show only UDP connections and listening sockets. Here’s how you can use the ss command to find the process listening on a specific port:
ss -u | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
ss -u | grep 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 22: Using the nestat command with the -n option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -n option, we can show numerical addresses instead of resolving them to hostnames. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -n | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22, you would run:
nestat -n | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 23: Using the lsof command with the -i udp:port -sUDP:LISTEN option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i udp:port -sUDP:LISTEN option, we can filter the output to only show UDP network-related information for a specific port in the LISTEN state. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i udp:<port> -sUDP:LISTENReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified port in the LISTEN state.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
lsof -i udp:53 -sUDP:LISTENThe output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 24: Using the fuser command with the -n tcp/udp port/tcp/udp option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp option, we can specify both the TCP and UDP protocols and the port number. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified ports.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 25: Using the ss command with the -n option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -n option, we can show numerical addresses instead of resolving them to hostnames. Here’s how you can use the ss command to find the process listening on a specific port:
ss -n | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22, you would run:
ss -n | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 26: Using the nestat command with the -p option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -p option, we can show the process ID (PID) and the process name associated with each network connection. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -p | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53, you would run:
nestat -p | grep 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 27: Using the lsof command with the -i tcp:port -sTCP:LISTEN -n option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i tcp:port -sTCP:LISTEN -n option, we can filter the output to only show TCP network-related information for a specific port in the LISTEN state, and display numerical addresses instead of resolving them to hostnames. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i tcp:<port> -sTCP:LISTEN -nReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified port in the LISTEN state, along with numerical addresses.
For example, to find the process listening on port 80 using the TCP protocol, you would run:
lsof -i tcp:80 -sTCP:LISTEN -nThe output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 28: Using the fuser command with the -n tcp/udp port/tcp/udp -n option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp -n option, we can specify both the TCP and UDP protocols and the port number, and display numerical addresses instead of resolving them to hostnames. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port> -nReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified ports, along with numerical addresses.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80 -nThe output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 29: Using the ss command with the -p option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -p option, we can show the process ID (PID) and the process name associated with each network connection. Here’s how you can use the ss command to find the process listening on a specific port:
ss -p | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 443, you would run:
ss -p | grep 443The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 30: Using the nestat command with the -l option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -l option, we can show only listening sockets. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -l | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 80, you would run:
nestat -l | grep 80The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 31: Using the lsof command with the -i udp:port -sUDP:LISTEN -n option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i udp:port -sUDP:LISTEN -n option, we can filter the output to only show UDP network-related information for a specific port in the LISTEN state, and display numerical addresses instead of resolving them to hostnames. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i udp:<port> -sUDP:LISTEN -nReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified port in the LISTEN state, along with numerical addresses.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
lsof -i udp:53 -sUDP:LISTEN -nThe output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 32: Using the fuser command with the -n tcp/udp port/tcp/udp -n option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp -n option, we can specify both the TCP and UDP protocols and the port number, and display numerical addresses instead of resolving them to hostnames. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port> -nReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified ports, along with numerical addresses.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80 -nThe output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 33: Using the ss command with the -l option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -l option, we can show only listening sockets. Here’s how you can use the ss command to find the process listening on a specific port:
ss -l | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 8080, you would run:
ss -l | grep 8080The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 34: Using the nestat command with the -t option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -t option, we can show only TCP connections and listening sockets. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -t | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22 using the TCP protocol, you would run:
nestat -t | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 35: Using the lsof command with the -i tcp:port -sTCP:LISTEN -n -P option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i tcp:port -sTCP:LISTEN -n -P option, we can filter the output to only show TCP network-related information for a specific port in the LISTEN state, display numerical addresses instead of resolving them to hostnames, and disable port name resolution. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i tcp:<port> -sTCP:LISTEN -n -PReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified port in the LISTEN state, along with numerical addresses and disabled port name resolution.
For example, to find the process listening on port 80 using the TCP protocol, you would run:
lsof -i tcp:80 -sTCP:LISTEN -n -PThe output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 36: Using the fuser command with the -n tcp/udp port/tcp/udp -n -m option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp -n -m option, we can specify both the TCP and UDP protocols and the port number, display numerical addresses instead of resolving them to hostnames, and enable additional information about the process. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port> -n -mReplace <port> with the desired port number. The command will display the process ID, process name, and additional information associated with the specified ports, along with numerical addresses.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80 -n -mThe output will provide the process ID, process name, and additional information, allowing you to identify the process associated with the port.
Method 37: Using the ss command with the -t option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -t option, we can show only TCP connections and listening sockets. Here’s how you can use the ss command to find the process listening on a specific port:
ss -t | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22 using the TCP protocol, you would run:
ss -t | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 38: Using the nestat command with the -u option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -u option, we can show only UDP connections and listening sockets. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -u | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
nestat -u | grep 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 39: Using the lsof command with the -i udp:port -sUDP:LISTEN -n -P option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i udp:port -sUDP:LISTEN -n -P option, we can filter the output to only show UDP network-related information for a specific port in the LISTEN state, display numerical addresses instead of resolving them to hostnames, and disable port name resolution. Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i udp:<port> -sUDP:LISTEN -n -PReplace <port> with the desired port number. The command will display the process ID and process name associated with the specified port in the LISTEN state, along with numerical addresses and disabled port name resolution.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
lsof -i udp:53 -sUDP:LISTEN -n -PThe output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 40: Using the fuser command with the -n tcp/udp port/tcp/udp -n -m option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp -n -m option, we can specify both the TCP and UDP protocols and the port number, display numerical addresses instead of resolving them to hostnames, and enable additional information about the process. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port> -n -mReplace <port> with the desired port number. The command will display the process ID, process name, and additional information associated with the specified ports, along with numerical addresses.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80 -n -mThe output will provide the process ID, process name, and additional information, allowing you to identify the process associated with the port.
Method 41: Using the ss command with the -u option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -u option, we can show only UDP connections and listening sockets. Here’s how you can use the ss command to find the process listening on a specific port:
ss -u | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53 using the UDP protocol, you would run:
ss -u | grep 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 42: Using the nestat command with the -n option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -n option, we can show numerical addresses instead of resolving them to hostnames. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -n | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22, you would run:
nestat -n | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 43: Using the lsof command with the -i tcp:port -sTCP:LISTEN -n -P -t option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i tcp:port -sTCP:LISTEN -n -P -t option, we can filter the output to only show TCP network-related information for a specific port in the LISTEN state, display numerical addresses instead of resolving them to hostnames, disable port name resolution, and show only the process ID (PID). Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i tcp:<port> -sTCP:LISTEN -n -P -tReplace <port> with the desired port number. The command will display the process ID associated with the specified port in the LISTEN state, along with numerical addresses, disabled port name resolution, and only the process ID (PID).
For example, to find the process listening on port 80 using the TCP protocol, you would run:
lsof -i tcp:80 -sTCP:LISTEN -n -P -tThe output will show the process ID, allowing you to identify the process responsible for the port.
Method 44: Using the fuser command with the -n tcp/udp port/tcp/udp -n -m -v option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp -n -m -v option, we can specify both the TCP and UDP protocols and the port number, display numerical addresses instead of resolving them to hostnames, enable additional information about the process, and show verbose output. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port> -n -m -vReplace <port> with the desired port number. The command will display the process ID, process name, additional information, and verbose output associated with the specified ports, along with numerical addresses.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80 -n -m -vThe output will provide the process ID, process name, additional information, and verbose output, allowing you to identify the process associated with the port.
Method 45: Using the ss command with the -n option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -n option, we can show numerical addresses instead of resolving them to hostnames. Here’s how you can use the ss command to find the process listening on a specific port:
ss -n | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22, you would run:
ss -n | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 46: Using the nestat command with the -p option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -p option, we can show the process ID (PID) and the process name associated with each network connection. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -p | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 53, you would run:
nestat -p | grep 53The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Method 47: Using the lsof command with the -i tcp:port -sTCP:LISTEN -n -P -t option
The lsof command is a powerful tool for listing open files and the processes that have them open. By using the -i tcp:port -sTCP:LISTEN -n -P -t option, we can filter the output to only show TCP network-related information for a specific port in the LISTEN state, display numerical addresses instead of resolving them to hostnames, disable port name resolution, show only the process ID (PID), and show only the process ID (PID). Here’s how you can use the lsof command to find the process listening on a specific port:
lsof -i tcp:<port> -sTCP:LISTEN -n -P -tReplace <port> with the desired port number. The command will display the process ID associated with the specified port in the LISTEN state, along with numerical addresses, disabled port name resolution, and only the process ID (PID).
For example, to find the process listening on port 80 using the TCP protocol, you would run:
lsof -i tcp:80 -sTCP:LISTEN -n -P -tThe output will show the process ID, allowing you to identify the process responsible for the port.
Method 48: Using the fuser command with the -n tcp/udp port/tcp/udp -n -m -v option
The fuser command is a simple yet effective tool for identifying processes using files or sockets. By using the -n tcp/udp port/tcp/udp -n -m -v option, we can specify both the TCP and UDP protocols and the port number, display numerical addresses instead of resolving them to hostnames, enable additional information about the process, and show verbose output. Here’s how you can use the fuser command to find the process listening on a specific port:
fuser -n tcp/udp <port>/<port> -n -m -vReplace <port> with the desired port number. The command will display the process ID, process name, additional information, and verbose output associated with the specified ports, along with numerical addresses.
For example, to find the process listening on port 80 using both the TCP and UDP protocols, you would run:
fuser -n tcp/udp 80/80 -n -m -vThe output will provide the process ID, process name, additional information, and verbose output, allowing you to identify the process associated with the port.
Method 49: Using the ss command with the -p option
The ss command is another powerful tool for displaying network socket information in Linux. By using the -p option, we can show the process ID (PID) and the process name associated with each network connection. Here’s how you can use the ss command to find the process listening on a specific port:
ss -p | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 443, you would run:
ss -p | grep 443The output will show the process ID and process name, allowing you to identify the process responsible for the port.
Method 50: Using the nestat command with the -l option
The nestat command is a versatile tool for displaying network-related information in Linux. By using the -l option, we can show only listening sockets. Here’s how you can use the nestat command to find the process listening on a specific port:
nestat -l | grep <port>Replace <port> with the desired port number. The command will display the process ID and process name associated with the specified port.
For example, to find the process listening on port 22, you would run:
nestat -l | grep 22The output will provide the process ID and process name, allowing you to identify the process associated with the port.
Conclusion
Identifying the process listening on a specific port is essential for troubleshooting network issues and ensuring the security of your Linux system. In this article, we explored various methods using command-line tools like netstat, ss, lsof, fuser, and sockstat to find the process associated with a specific port. By following the step-by-step instructions provided for each method, you can easily determine which process is listening on a particular port in your Linux system. Remember to choose the method that best suits your needs and preferences. Happy troubleshooting!
FAQs
Q: Can I use these methods to find the process listening on a remote port?
A: No, these methods are primarily used to find the process listening on a port in your local Linux system. To find the process listening on a remote port, you would need to use network monitoring tools or connect to the remote system and run the appropriate commands.
Q: What if I don’t have access to the command-line tools mentioned in the article?
A: If you don’t have access to the command-line tools mentioned in the article, you can try using alternative tools or consult your system administrator for assistance. Additionally, some graphical user interface (GUI) network monitoring tools may provide similar functionality.
Q: Can I use these methods to find the process listening on a specific port in Windows?
A: No, these methods are specific to Linux systems. In Windows, you would need to use different command-line tools or graphical user interface (GUI) tools to find the process listening on a specific port.
