You can use any one of the following command to find out what is using tcp or udp port number 80 on Linux operating systems:
- netstat – a command-line tool that displays network connections, routing tables, and a number of network interface statistics.
- fuser – a command line tool to identify processes using files or sockets.
- lsof – a command line tool to list open files under Linux / UNIX to report a list of all open files and the processes that opened them.
- /proc/$pid/ file system – Under Linux /proc includes a directory for each running process (including kernel processes) at /proc/PID, containing information about that process, notably including the processes name that opened port.
| Tutorial details | |
|---|---|
| Difficulty | Easy (rss) |
| Root privileges | No |
| Requirements | None |
| Time | 1m |
Examples
Open a terminal and then type the following command as root user:
netstat command find out what is using port 80
Type the following command
# netstat -tulpn | grep :80
OR pass the –color option to grep command as follows:
# netstat -tulpn | grep --color :80
Sample outputs:
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1215/nginx
Where,
- 0 0.0.0.0:80 – Source IP:Port
- 1215/nginx – PID/Process name
The tcp port 80 is opened and used by nginx web server. Type the following command to find out more about nginx:
whatis nginx whereis nginx
Note: You may need to install lsof and fuser command.
Use /proc/$pid/exec file find out what is using port 80
First, find out the processes PID that opened tcp port 90, enter:
# fuser 80/tcp
Sample outputs:
80/tcp: 12161 21776 25250 25393
Finally, find out process name associated with PID # 3813, enter:
# ls -l /proc/12161/exe
Sample outputs:
lrwxrwxrwx. 1 root root 0 Aug 9 13:28 /proc/12161/exe -> /usr/sbin/lighttpd
Find out more about lighttpd:
man lighttpd whatis lighttpd whereis lighttpd
Sample outputs:
lighttpd (8) - a fast, secure and flexible web server lighttpd: /usr/sbin/lighttpd /usr/lib64/lighttpd /usr/share/man/man8/lighttpd.8.gz
You can use package manager to dig into lighttpd:
# rpm -qa | grep lighttpd
Sample outputs:
lighttpd-1.4.32-1.el6.x86_64
To find out more about lighttpd-1.4.32-1.el6.x86_64 package, type:
# yum info lighttpd-1.4.32-1.el6.x86_64
Sample outputs:
Loaded plugins: auto-update-debuginfo, protectbase, rhnplugin, security
This system is receiving updates from RHN Classic or RHN Satellite.
0 packages excluded due to repository protections
Installed Packages
Name : lighttpd
Arch : x86_64
Version : 1.4.32
Release : 1.el6
Size : 664 k
Repo : installed
Summary : A web server more optimized for speed-critical environments.
URL : http://lighttpd.net/
License : Revised BSD
Description : It is a secure and fast web server a very low memory footprint compared
: to other webservers and takes care of cpu-load.
OR use rpm command:
# rpm -qi lighttpd
Sample outputs:
Name : lighttpd Relocations: (not relocatable) Version : 1.4.32 Vendor: nixCraft Release : 1.el6 Build Date: Sun 03 Feb 2013 03:22:08 AM CST Install Date: Mon 04 Feb 2013 04:44:26 AM CST Build Host: rhel6.nixcraft.net.in Group : System Environment/Daemons Source RPM: lighttpd-1.4.32-1.el6.src.rpm Size : 680402 License: Revised BSD Signature : (none) URL : http://lighttpd.net/ Summary : A web server more optimized for speed-critical environments. Description : It is a secure and fast web server a very low memory footprint compared to other webservers and takes care of cpu-load.
Debian / Ubuntu Linux user can use the following commands:
# dpkg --list | grep lighttpd
# apt-cache search lighttpd
# apt-cache show lighttpd
Sample outputs from the last command:
Package: lighttpd Priority: optional Section: universe/web Installed-Size: 841 Maintainer: Ubuntu Developers Original-Maintainer: Debian lighttpd maintainers Architecture: amd64 Version: 1.4.28-2ubuntu4 Provides: httpd, httpd-cgi Depends: libattr1 (>= 1:2.4.46-5), libbz2-1.0, libc6 (>= 2.4), libgamin0 | libfam0, libldap-2.4-2 (>= 2.4.7), libpcre3 (>= 8.10), libssl1.0.0 (>= 1.0.0), zlib1g (>= 1:1.1.4), lsb-base (>= 3.2-14), mime-support, libterm-readline-perl-perl Recommends: spawn-fcgi Suggests: openssl, rrdtool, apache2-utils, ufw Conflicts: cherokee (lsof command find out what is using port 80
Type the following command
# lsof -i :80 | grep LISTEN
Sample outputs:apache2 1607 root 3u IPv4 6472 0t0 TCP *:www (LISTEN) apache2 1616 www-data 3u IPv4 6472 0t0 TCP *:www (LISTEN) apache2 1617 www-data 3u IPv4 6472 0t0 TCP *:www (LISTEN)See also
- Linux: Find Out Which Process Is Listening Upon a Port
- ss: Display Linux TCP / UDP Network and Socket Information
- See man pages for more info ss(8)
🐧 Get the latest tutorials on Linux, Open Source & DevOps via RSS feed or Weekly email newsletter.
🐧 5 comments so far... add one ↓
🐧 5 comments so far... add one ↓
Related Tutorials
| Category | List of Unix and Linux commands |
|---|---|
| File Management | cat |
| Firewall | Alpine Awall • CentOS 8 • OpenSUSE • RHEL 8 • Ubuntu 16.04 • Ubuntu 18.04 • Ubuntu 20.04 |
| Network Utilities | dig • host • ip • nmap |
| OpenVPN | CentOS 7 • CentOS 8 • Debian 10 • Debian 8/9 • Ubuntu 18.04 • Ubuntu 20.04 |
| Package Manager | apk • apt |
| Processes Management | bg • chroot • cron • disown • fg • jobs • killall • kill • pidof • pstree • pwdx • time |
| Searching | grep • whereis • which |
| User Information | groups • id • lastcomm • last • lid/libuser-lid • logname • members • users • whoami • who • w |
| WireGuard VPN | Alpine • CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04 |
Hi,
Thanks a lot,
i forwarded this article to my students
you should introduce ss instead of netstat, because the later one is deprecated.
See “See also” section at the bottom of the faq.
I find ss to be MUCH faster then netstat. It lacks all the detailed output for netstat is perfect for the question asked. Also ss is great for scripts because of its speed. Especially for boxes that have hundreds to thousands of connections.
ss -anl4
emathis@emathis-lappy:~$ time ss -anl &> /dev/null ; time netstat -anl &>/dev/null
real 0m0.009s
user 0m0.000s
sys 0m0.000s
real 0m0.024s
user 0m0.008s
sys 0m0.012s
Hi
thank you