![\"\"](\"https:\/\/imagedelivery.net\/LqiWLm-3MGbYHtFuUbcBtA\/wp-content\/uploads\/sites\/2\/2022\/11\/eBook-Speed-Up-your-website.png\/w=1024,h=1024,fit=scale-down\")
<\/a><\/figure>What Is Keep-Alive<\/h2>
Keep-Alive, also known as a persistent connection, is a communication pattern between a server and a client to reduce the HTTP request amount and speed up a web page.<\/p>
When Keep-Alive is turned on, the client and the server agree to keep the connection for subsequent requests or responses open.<\/p>
How Does Keep-Alive Work<\/h2>
By default, HTTP connections close at the end of data transactions. This means that clients create a new connection to request each file of a page and servers close these TCP connections after sending the data.<\/p>
However, if a server needs to respond to multiple HTTP requests simultaneously and serve a single file for each new TCP connection, the site page’s load time will be increased. This can lead to a poor user experience.<\/p>
To overcome this issue, website owners need to enable the Keep-Alive header to limit the number of new connections.<\/p>
By turning the Keep-Alive connection header on, clients can download all the content such as JavaScript<\/a>, CSS, images, and videos through a single TCP connection instead of sending a different request for each file.<\/p> Here’s a picture to demonstrate how Keep-Alive works:<\/p> Keep-Alive can improve website speed<\/a> and performance as it maintains an open connection between a client and a server, saving the time needed to serve <\/strong>files.<\/p> Enabling Keep-Alive has additional benefits, such as:<\/p> The file you need to prepare before enabling the HTTP Keep-Alive header depends on what server you use and your access privileges.<\/p> Make sure that you have access to one of the following files before continuing this guide:<\/p> When you’re finished, follow these steps to enable Keep-Alive:<\/p> Although many hosting providers have Keep-Alive enabled by default, some of them might have this header disabled for performance reasons.<\/p> To check whether Keep-Alive is enabled on your server, run a website speed test<\/a> using a tool such as GTMetrix<\/strong><\/a>.<\/p> Hostinger users can also use the page speed test<\/strong> feature on hPanel to check if Keep-Alive is working properly. You can access it by opening the hPanel dashboard and then going to the Performance → Page Speed<\/strong> section.<\/p> Choose the website you want to test and the type of device. Click Analyze, then wait until the process is complete. If Keep-Alive is working properly, you should see a good score.<\/p> If the analysis tool shows that Keep-Alive is disabled, move to the next step.<\/p> To enable Keep-Alive, you need to explicitly request it via the HTTP header by accessing .htaccess<\/strong> or the main configuration file of your web server. If you turn on Keep-Alive, the HTTP response header will show The following tutorial will cover four different methods to enable Keep-Alive on your server.<\/p> Enable Keep-Alive and override any server settings by adding the following code to your .htaccess<\/strong> file:<\/p> This method should work on most Linux-based shared hosting providers. If you use Hostinger, locate the .htaccess file using the File Manager<\/strong>.<\/p> To do that, open the hPanel dashboard, then click the File Manager<\/strong> button. You can find the .htaccess<\/strong> file under the public_html<\/strong> folder. Right-click on the file, then choose edit<\/strong> to add the code.<\/p> Make sure to test your website for any errors after editing the .htaccess<\/strong> file.<\/p> If you have access to the Apache configuration file, it’s possible to enable the extension from there.<\/p> To locate the httpd.conf<\/strong> file, enter the following command into the command line:<\/p> The following parameters affect Keep-Alive functionality in Apache, from enabling the persistent connection to defining the idle connection timeout:<\/p> Here is what the configuration should look like:<\/p> As a web server and reverse proxy, NGINX<\/a> has Keep-Alive enabled by default. In some cases, however, it may be disabled. Users can enable it using ngx_http_core_module<\/a>.<\/p> Look for the value Before deleting the value to enable Keep-Alive, make sure to find out why it was disabled in the first place.<\/p> If you use a Windows-based server, enable the Keep-Alive extension through the command line.<\/p> The following command will enable it:<\/p> If you wish to disable Keep-Alive, use:<\/p> Windows Server users can also enable the Keep-Alive header by editing the configuration files directly or writing WMI scripts<\/a>.<\/p> Once Keep-Alive is enabled, run another scan with GTMetrix or KeyCDN’s HTTP Header Checker<\/a> to see whether the extension is active.<\/p> It’s also possible to check the HTTP header via the terminal using the following command:<\/p> In the following example, we’ll check the HTTP header of hostinger.com<\/strong>:<\/p> This gives us the following results:<\/p> The ![\"A](\"https:\/\/imagedelivery.net\/LqiWLm-3MGbYHtFuUbcBtA\/wp-content\/uploads\/sites\/2\/2022\/03\/keep-alive.jpg\/public\")
<\/a><\/figure>Advantages of Enabling Keep-Alive<\/h2>
\n
Requirements Before Enabling HTTP Keep-Alive<\/h2>
\n
1. Test your Website’s Speed<\/h2>
![\"A](\"https:\/\/imagedelivery.net\/LqiWLm-3MGbYHtFuUbcBtA\/wp-content\/uploads\/sites\/2\/2021\/08\/GTmetrix-1.png\/w=1024,h=1024,fit=scale-down\")
<\/a><\/figure>![\"The](\"https:\/\/imagedelivery.net\/LqiWLm-3MGbYHtFuUbcBtA\/wp-content\/uploads\/sites\/2\/2023\/03\/hpanel-hosting-performance-pagespeed-sidebar.png\/public\")
<\/a><\/figure><\/div>![\"hPanel](\"https:\/\/imagedelivery.net\/LqiWLm-3MGbYHtFuUbcBtA\/wp-content\/uploads\/sites\/2\/2016\/12\/hpanel-performance-pagespeed-result.png\/public\")
<\/a><\/figure><\/div>2. Enable Keep-Alive<\/h2>
Connection: keep-alive.<\/code><\/p>Option 1 – Edit the .htaccess file<\/h3>
<ifModule mod_headers.c>\nHeader set Connection keep-alive\n<\/ifModule><\/pre>
![\"The](\"https:\/\/imagedelivery.net\/LqiWLm-3MGbYHtFuUbcBtA\/wp-content\/uploads\/sites\/2\/2021\/08\/filemanager-publichtml-htaccess-edit.png\/w=1024,h=1024,fit=scale-down\")
<\/a><\/figure><\/div>Option 2 – Enable Keep-Alive in Apache via httpd.conf file<\/h3>
find \/ -name httpd.conf<\/pre>
\n
KeepAlive On<\/code> to enable the extension or KeepAlive Off<\/code> <\/strong>to disable it.<\/li>\n\n\n\n#\n# KeepAlive: Whether or not to allow persistent connections (more than\n# one request per connection). Set to \"Off\" to deactivate.\n#\nKeepAlive On\n\n#\n# MaxKeepAliveRequests: The maximum number of requests to allow\n# during a persistent connection. Set to 0 to allow an unlimited amount.\n# We recommend you leave this number high, for maximum performance.\n#\nMaxKeepAliveRequests 50\n\n#\n# KeepAliveTimeout: Number of seconds to wait for the next request from the\n# same client on the same connection.\n#\nKeepAliveTimeout 10<\/pre>
Option 3 – Enable Keep-Alive Header in NGINX<\/h3>
keepalive_disable<\/code> – in most cases, this will be the reason why Keep-Alive is not working.<\/p>Option 4 – Enable Keep-Alive in Windows Server (IIS)<\/h3>
appcmd set config \/section:httpProtocol \/allowKeepAlive:true<\/pre>
appcmd set config \/section:httpProtocol \/allowKeepAlive:false<\/pre>
3. Test the changes<\/h2>
curl -I http:\/\/example.com\/example.php<\/pre>
curl -i http:\/\/hostinger.com\/index.php<\/pre>
HTTP\/1.1 301 Moved Permanently\nDate: Tue, 27 Jul 2021 01:55:24 GMT\nTransfer-Encoding: chunked\nConnection: keep-alive\nCache-Control: max-age=3600\nExpires: Tue, 27 Jul 2021 02:55:24 GMT\nLocation: \/index.php<\/pre>
Connection: keep-alive<\/code> part shows that Keep-Alive is functional.<\/p>![\"Hostinger](\"https:\/\/imagedelivery.net\/LqiWLm-3MGbYHtFuUbcBtA\/wp-content\/uploads\/sites\/2\/2023\/11\/Web-hosting_in-text-banner.png\/public\")
<\/a><\/figure>Conclusion<\/h2>