{"id":12447,"date":"2019-03-27T01:27:24","date_gmt":"2019-03-27T01:27:24","guid":{"rendered":"http:\/\/www.appservgrid.com\/paw92\/?p=12447"},"modified":"2019-03-27T01:27:24","modified_gmt":"2019-03-27T01:27:24","slug":"4-ways-to-find-out-what-ports-are-listening-in-linux","status":"publish","type":"post","link":"https:\/\/www.appservgrid.com\/paw92\/index.php\/2019\/03\/27\/4-ways-to-find-out-what-ports-are-listening-in-linux\/","title":{"rendered":"4 Ways to Find Out What Ports Are Listening in Linux"},"content":{"rendered":"

The state of a port is either\u00a0open<\/strong>,\u00a0filtered<\/strong>,\u00a0closed<\/strong>, or\u00a0unfiltered<\/strong>. A port is said to be open if an application on the target machine is listening for connections\/packets on that port.<\/p>\n

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.<\/p>\n

1. Using Netstat Command<\/h3>\n

Netstat<\/a>\u00a0is a widely used tool for querying information about the Linux networking subsystem. You can use it to print all open ports like this:<\/p>\n

$ sudo netstat -ltup \r\n<\/pre>\n
The flag\u00a0-l<\/code>\u00a0tells netstat to print all listening sockets,\u00a0-t<\/code>\u00a0shows all TCP connections,\u00a0-u<\/code>\u00a0displays all UDP connections and\u00a0-p<\/code>\u00a0enables printing of application\/program name listening on the port.<\/p>\n
\n
\"Check<\/a><\/p>\n
Check Open Ports Using Netstat Command<\/p>\n
 <\/p>\n<\/div>\n
To print numeric values rather than service names, add the\u00a0-n<\/code>\u00a0flag.<\/p>\n
$ sudo netstat -lntup\r\n<\/pre>\n
\n
\"Show<\/a><\/p>\n
Show Numeric Values<\/p>\n<\/div>\n
You can also use\u00a0grep command<\/a>\u00a0to find out which application is listening on a particular port, for example.<\/p>\n
$ sudo netstat -lntup | grep \"nginx\"\r\n<\/pre>\n
\n
\"Find<\/a><\/p>\n
Find Port of Running Application<\/p>\n<\/div>\n
Alternatively, you can specify the port and find the application bound to, as shown.<\/p>\n
$ sudo netstat -lntup | grep \":80\"\r\n<\/pre>\n
\n
\"Find<\/a><\/p>\n
Find Application Using a Port Number<\/p>\n<\/div>\n
2. Using ss Command<\/h3>\n
ss<\/strong>\u00a0is another useful tool for displaying information about sockets. It\u2019s output looks similar to that of\u00a0netstat<\/strong>. The following command will show all listening ports for\u00a0TCP<\/strong>\u00a0and\u00a0UDP<\/strong>\u00a0connections in numeric value.<\/p>\n
$ sudo ss -lntu\r\n<\/pre>\n
\n
\"Find<\/a><\/p>\n
Find Open Ports Using ss Command<\/p>\n<\/div>\n
3. Using Nmap Command<\/h3>\n
Nmap<\/a>\u00a0is a powerful and popular network exploration tool and port scanner. To install nmap on your system, use your default package manager as shown.<\/p>\n
$ sudo apt install nmap  [On Debian\/Ubuntu]\r\n$ sudo yum install nmap  [On CentOS\/RHEL]\r\n$ sudo dnf install nmap  [On Fedora 22+]\r\n<\/pre>\n
To scan all open\/listening ports in your Linux system, run the following command (which should take a long time to complete).<\/p>\n
$ sudo nmap -n -PN -sT -sU -p- localhost\r\n<\/pre>\n
4. Using lsof Command<\/h3>\n
The final tool we will cover for querying open ports is\u00a0lsof command<\/a>, which is used to list open files in Linux. Since\u00a0everything is a file in Unix\/Linux<\/a>, an open file may be a stream or a network file.<\/p>\n
To list all Internet and network files, use the\u00a0-i<\/code>\u00a0option. Note that this command shows a mix of service names and numeric ports.<\/p>\n
$ sudo lsof -i\r\n<\/pre>\n
\n
\"List<\/a><\/p>\n
List Open Network Files Using lsof Command<\/p>\n<\/div>\n
To find which application is listening on a particular port, run\u00a0lsof<\/strong>\u00a0in this form.<\/p>\n
$ sudo lsof -i :80\r\n<\/pre>\n
\n
\"Find<\/a><\/p>\n
Find Application Using Port<\/p>\n<\/div>\n
That\u2019s 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.<\/p>\n
Source<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
The state of a port is either\u00a0open,\u00a0filtered,\u00a0closed, or\u00a0unfiltered. 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 … <\/p>\n
Continue reading “4 Ways to Find Out What Ports Are Listening in Linux”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-12447","post","type-post","status-publish","format-standard","hentry","category-linux"],"_links":{"self":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts\/12447","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/comments?post=12447"}],"version-history":[{"count":1,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts\/12447\/revisions"}],"predecessor-version":[{"id":12448,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts\/12447\/revisions\/12448"}],"wp:attachment":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/media?parent=12447"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/categories?post=12447"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/tags?post=12447"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}