Linux netstat all listening ports

Содержание
  1. Linux netstat all listening ports
  2. Check ports
  3. Filter the list
  4. Analyze the results
  5. Share this information:
  6. 4 Ways to Find Out What Ports Are Listening in Linux
  7. 1. Using Netstat Command
  8. 2. Using ss Command
  9. 3. Using Nmap Command
  10. 4. Using lsof Command
  11. If You Appreciate What We Do Here On TecMint, You Should Consider:
  12. 11 примеров использования netstat
  13. 1. Список всех портов (как прослушиваемых, так и нет)
  14. 2. Список сокетов, находящихся в состоянии LISTEN
  15. 3. Просмотр статистики для каждого протокола
  16. 4. Отображение PID и имени процесса в выводе netstat
  17. 5. Разрешение имён в выводе netstat
  18. 6. Вывод информации netstat непрерывно
  19. 7. Неподдерживаемые системой семейства адресов
  20. 8. Маршрутизация ядра
  21. 9. Соответствие портов и процессов
  22. 10. Сетевые интерфейсы
  23. 11. netstat -lnptux
  24. 20 Netstat Commands for Linux Network Management
  25. 1. Listing all the LISTENING Ports of TCP and UDP Connections
  26. 2. Listing TCP Ports connections
  27. 3. Listing UDP Ports connections
  28. 4. Listing all LISTENING Connections
  29. 5. Listing all TCP Listening Ports
  30. 6. Listing all UDP Listening Ports
  31. 7. Listing all UNIX Listening Ports
  32. 8. Showing Statistics by Protocol
  33. 9. Showing Statistics by TCP Protocol
  34. 10. Showing Statistics by UDP Protocol
  35. 11. Displaying Service name with PID
  36. 12. Displaying Promiscuous Mode
  37. 13. Displaying Kernel IP routing
  38. 14. Showing Network Interface Transactions
  39. 15. Showing Kernel Interface Table
  40. 16. Displaying IPv4 and IPv6 Information
  41. 17. Print Netstat Information Continuously
  42. 18. Finding non-supportive Address
  43. 19. Finding Listening Programs
  44. 20. Displaying RAW Network Statistics
  45. If You Appreciate What We Do Here On TecMint, You Should Consider:
  46. Related Posts
  47. 18 thoughts on “20 Netstat Commands for Linux Network Management”

Linux netstat all listening ports

Last updated on: 2018-12-21

Authored by: Rackspace Support

If you’re troubleshooting a service that you know is running normally, the next step is to ensure it’s listening on the correct network port.

The netstat command shows the services listening to ports on a Linux server and the details of any connections currently made to them. The connection details to consider during basic network daemon troubleshooting are the addresses that the daemon is listening on (including the port number), the daemon’s process identifier (PID), and the program name.

You need to run netstat on the server that is running the service. Netstat is not affected by your firewall configuration.

Note: You can also use the lsof and ss commands to check ports. Many of the command flags contained in this article are the same when you run the lsof and ss commands. However, the output returned when you use these commands might not resemble the output of the netstat tool. For more information about both commands, see the lsof and ss command manuals.

Check ports

To list the TCP ports that are being listened on, and the name of each listener’s daemon and its PID, run the following command:

The following example shows the output for three common programs that are listening on three different sockets.

Filter the list

If the list of listening daemons is long, you can use grep to filter it. For example, to filter out everything except the default web server port 80 , run the following command:

Analyze the results

Common outcomes include the following results:

  • Nothing is listening on the port. Check the service configuration files, and then restart the service.
  • The correct service is listening on the correct port. In this case you need to test the service more thoroughly. Skip to the article on testing the listening service for response using netcat.
  • Something other than the expected service appears to be listening on the port.

Note: A super-server, such as xinetd, might be listening on the port. Check your xinetd configuration to ensure that this behavior is acceptable.

If something else is listening on the port, you can disable the program by running sudo service httpd stop , or change its configuration so that it no longer listens on the port. When netstat shows the port is free, enable the correct service (for example sudo service vsftpd start ).

If you make any changes because the incorrect service is listening, run the netstat command again. If netstat doesn’t show the program listening on the correct port, you need to address its configuration before you go any further.

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If you make changes at this point, be sure to test your setup to verify that you have resolved your issue.

If using the netstat did not resolve your port issues, continue to test connections to the service by using the netcat command.

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©2020 Rackspace US, Inc.

Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License

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4 Ways to Find Out What Ports Are Listening in Linux

The state of a port is either open, filtered, closed, or unfiltered. A port is said to be open if an application on the target machine is listening for connections/packets on that port.

In this article, we will explain four ways to check open ports and also will show you how to find which application is listening on what port in Linux.

1. Using Netstat Command

Netstat is a widely used tool for querying information about the Linux networking subsystem. You can use it to print all open ports like this:

The flag -l tells netstat to print all listening sockets, -t shows all TCP connections, -u displays all UDP connections and -p enables printing of application/program name listening on the port.

Check Open Ports Using Netstat Command

To print numeric values rather than service names, add the -n flag.

Show Numeric Values

You can also use grep command to find out which application is listening on a particular port, for example.

Find Port of Running Application

Alternatively, you can specify the port and find the application bound to, as shown.

Find Application Using a Port Number

2. Using ss Command

ss command is another useful tool for displaying information about sockets. It’s output looks similar to that of netstat. The following command will show all listening ports for TCP and UDP connections in numeric value.

Find Open Ports Using ss Command

3. Using Nmap Command

Nmap is a powerful and popular network exploration tool and port scanner. To install nmap on your system, use your default package manager as shown.

To scan all open/listening ports in your Linux system, run the following command (which should take a long time to complete).

4. Using lsof Command

The final tool we will cover for querying open ports is lsof command, which is used to list open files in Linux. Since everything is a file in Unix/Linux, an open file may be a stream or a network file.

To list all Internet and network files, use the -i option. Note that this command shows a mix of service names and numeric ports.

List Open Network Files Using lsof Command

To find which application is listening on a particular port, run lsof in this form.

Find Application Using Port

That’s all! In this article, we have explained four ways to check open ports in Linux. We also showed how to check which processes are bound upon particular ports. You can share your thoughts or ask any questions via the feedback form below.

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11 примеров использования netstat

Команда netstat, входящая в стандартный набор сетевых инструментов UNIX, отображает различную network–related информацию, такую как сетевые подключения, статистику интерфейсов, таблицы маршрутизации, masquerade, multicast, и т.п.

В этой статье рассмотрим десять практических примеров использования команды netstat в Linux.

1. Список всех портов (как прослушиваемых, так и нет)

Перечислить все порты: netstat -a

Перечислить все TCP порты: netstat -at

Перечислить все UDP порты: netstat -au

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2. Список сокетов, находящихся в состоянии LISTEN

Перечислить все прослушиваемые порты: netstat -l

Перечислить прослушиваемые TCP порты: netstat -lt

Перечислить прослушиваемые UDP порты: netstat -lu

Перечислить прослушиваемые UNIX сокеты: netstat -lx

3. Просмотр статистики для каждого протокола

Показать статистику всех портов: netstat -s

Показать статистику только TCP портов: netstat -st

Показать статистику только UDP портов: netstat -su

4. Отображение PID и имени процесса в выводе netstat

Опция netstat -p добавит «PID/Program Name» в вывод netstat, и может быть совмещена с любым другим набором опций. Это очень полезно при отладке, для определения того, какая программа работает на определённом порту.

5. Разрешение имён в выводе netstat

Когда вам не нужно резолвить имя хоста, имя порта, имя пользователя, используйте опцию netstat -n для вывода значений в цифровом формате. Команда покажет IP-адрес вместо хоста, номер порта вместо имени порта, UID вместо имени пользователя.

Это также ускорит вывод, так как netstat не станет выполнять ненужный поиск.

Для вывода цифровых значений только некоторых из этих пунктов, используйте следующие команды:

6. Вывод информации netstat непрерывно

Опция netstat -c будет выводить информацию непрерывно, в стиле top, обновляя экран каждые несколько секунд.

7. Неподдерживаемые системой семейства адресов

Опция netstat —verbose покажет подробный вывод, а в самом конце отобразит неподдерживаемые Address Family.

8. Маршрутизация ядра

Показать таблицу маршрутизации ядра: netstat -r

Примечание: Используйте netstat -rn для просмотра маршрута в цифровом формате без разрешения имён узлов.

9. Соответствие портов и процессов

Узнать, какой порт занимает определённая программа:

Выяснить, каким процессом используется определённый порт:

10. Сетевые интерфейсы

Показать список сетевых интерфейсов: netstat -i

Показать расширенную информацию об интерфейсах (аналогично ifconfig): netstat -ie

11. netstat -lnptux

Резюмируем вышеописанное и объединим ключи в одну полезную команду, которая покажет:

  • -l все открытые порты (LISTEN)
  • -t по протоколу TCP
  • -u по протоколу UDP
  • -x по протоколу UNIX Socket
  • -n без резолва IP/имён
  • -p но с названиями процессов и PID-ами

Примечание: Не все процессы могут быть идентифицированы последним ключом, чужие процессы показаны не будут. Вы должны иметь права root чтобы увидеть всё.

Источник

20 Netstat Commands for Linux Network Management

netstat (network statistics) is a command-line tool for monitoring network connections both incoming and outgoing as well as viewing routing tables, interface statistics, etc.

netstat is available on all Unix-like Operating Systems and also available on Windows OS as well. It is very useful in terms of network troubleshooting and performance measurement.

netstat is one of the most basic network service debugging tools, telling you what ports are open and whether any programs are listening on ports.

Update: The Linux netstat command is replaced by new ss command, which is capable of displaying more information about network connections and it is much faster than the older netstat command.

The netstat tool is very important and much useful for Linux network administrators as well as system administrators to monitor and troubleshoot their network-related problems and determine network traffic performance.

This article shows usages of netstat command with their examples which may be useful in daily operation.

1. Listing all the LISTENING Ports of TCP and UDP Connections

Listing all ports (both TCP and UDP) using netstat -a option.

2. Listing TCP Ports connections

Listing only TCP (Transmission Control Protocol) port connections using netstat -at.

3. Listing UDP Ports connections

Listing only UDP (User Datagram Protocol ) port connections using netstat -au.

4. Listing all LISTENING Connections

Listing all active listening ports connections with netstat -l.

5. Listing all TCP Listening Ports

Listing all active listening TCP ports by using option netstat -lt.

6. Listing all UDP Listening Ports

Listing all active listening UDP ports by using option netstat -lu.

7. Listing all UNIX Listening Ports

Listing all active UNIX listening ports using netstat -lx.

8. Showing Statistics by Protocol

Displays statistics by protocol. By default, statistics are shown for the TCP, UDP, ICMP, and IP protocols. The -s parameter can be used to specify a set of protocols.

9. Showing Statistics by TCP Protocol

Showing statistics of only TCP protocol by using option netstat -st.

10. Showing Statistics by UDP Protocol

11. Displaying Service name with PID

Displaying service name with their PID number, using option netstat -tp will display “PID/Program Name“.

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12. Displaying Promiscuous Mode

Displaying Promiscuous mode with -ac switch, netstat print the selected information or refresh screen every five seconds. The default screen refreshes every second.

13. Displaying Kernel IP routing

Display Kernel IP routing table with netstat and route command.

14. Showing Network Interface Transactions

Showing network interface packet transactions including both transferring and receiving packets with MTU size.

15. Showing Kernel Interface Table

Showing Kernel interface table, similar to ifconfig command.

16. Displaying IPv4 and IPv6 Information

Displays multicast group membership information for both IPv4 and IPv6.

17. Print Netstat Information Continuously

To get netstat information every few seconds, then use the following command, it will print netstat information continuously, say every few seconds.

18. Finding non-supportive Address

Finding un-configured address families with some useful information.

19. Finding Listening Programs

Find out how many listening programs running on a port.

20. Displaying RAW Network Statistics

That’s it, If you are looking for more information and options about the netstat command, refer to netstat manual docs or use the man netstat command to know all the information.

If we’ve missed anything in the list, please inform us using our comment section below. So, we could keep updating this list based on your comments.

If You Appreciate What We Do Here On TecMint, You Should Consider:

TecMint is the fastest growing and most trusted community site for any kind of Linux Articles, Guides and Books on the web. Millions of people visit TecMint! to search or browse the thousands of published articles available FREELY to all.

If you like what you are reading, please consider buying us a coffee ( or 2 ) as a token of appreciation.

We are thankful for your never ending support.

18 thoughts on “20 Netstat Commands for Linux Network Management”

Hi, This is Bala,

This article is very help to us, but one thing netstat command is used to display the information only or we can able to edit the network settings?

Here you will mentioning display the information only, if i want to edit the some TCP/UDP port means how can i do this?

The command netstat is used to display network related information only, to configure network check our articles at tecmint.com.

Can I take this data for 1 hr. For example I want dump or data of this command from 1 PM to 2 PM.
Please suggest.

is there a way of generating logs reports of proxy server like sarg , squidAnalyzer. there has major drawback , the url link not generate accurates,

i want a software tools or hardware tools , for generating accurate url link of client or user of Network.

but possible in Linux

We’ll have to check out such a tool. We hope you can wait a little as we try to find one.

What is the best way to go about finding all ports being used by MySQL for clustering purposes?

I am on Linux platform with MySQL NDB 5.7. I am trying to monitor all traffic related to MySQL clustering – between data nodes, management node and sql nodes. To that end, I used netstat to list all open ports listening on my machine before starting MySQL cluster.

Then, I started MySQL cluster and ran netstat again. I assumed that the ports that were listening the second time around, but not the first time, were related to MySQL clustering.

But there are two problems with this. First, there could be ports opened by other processes between the two netstat runs. Second, MySQL might open other ports after I ran the netstat command the second time.

What is the best way to go about finding all ports being used by MySQL for clustering purposes?

I believe ephemeral ports are picked dynamically, so perhaps if I knew all the MySQL clustering related processes that would be running, I can figure out every port that they are using. Pointers will be very welcome.

netstat -tlnpl

This command will indicate the port number and process ID(PID)/program name as well.

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