Persistent Connection Checking Tool

How do you check if your website is using Persistent Connection?

You can easily check if your website supports Persistent Connection by following these steps:

• Enter your website in the above URL field (If you have to check multiple URLs switch to the Bulk mode).

• Click on the Check button.

• We will analyse your web server and let you know if it uses a Persistent Connection.

• If not, we will tell you how to enable it on your web server.

• We will also check if there are external server calls and give you the option to bulk check the Persistent Connection status of those servers.

Does your server support Persistent Connection?

The default HTTP 1.0 connection is usually closed after each request has been completed, meaning that the server closes the TCP connection after delivering the response. In order to keep the connection open for multiple requests, the keep-alive connection header can be used. In HTTP 1.1 connection is open by default unless the server or client explicitly sets it to close. In HTTP 2 connection is always open. The Connection: close header is ignored on HTTP 2.0

Here is a table outlining if the client server connection is a persistent connection.

How to enable Persistent Connection using httpd.conf on Apache Servers?

In most cases Keep-alive should be enabled automatically if you are using HTTP 1.1 or above. To enable Connection: Keep-Alive all you have to do is edit your Apache config file. It is usually found at /etc/httpd/conf/httpd.conf

There are three settings you can modify here:

• KeepAlive: Set it to "KeepAlive on" to enable keep-alive.

• MaxKeepAliveRequests: Sets the maximum number of requests to allow during a persistent connection. Set it to "MaxKeepAliveRequests 60"

• KeepAliveTimeout: Sets how long your server should wait for new requests from clients. Set it to "KeepAliveTimeout 3"

NOTE: Web server will usually have a concurrency limit or scalability problem, and when they hit that limit, performance will drop. Keep in mind there are no one-size-fits-all numbers for MaxKeepAliveRequests and KeepAliveTimeout, so speak to you hosting provider OR Webmaster to see what numbers work best for you.

How to enable Connection: Keep-Alive on LiteSpeed Servers?

Persistent Connection is enabled by default for LiteSpeed Servers, there is no "yes/no" or "on/off" option its server settings. But you can go into LSWS Admin Console -> Server -> Tuning -> Connection section to modify the Max Keep-Alive Requests, Smart Keep-Alive, and Keep-Alive Timeout (secs) settings.

NOTE: Smart Keep-Alive is a feature in LiteSpeed Servers that is useful for high volume websites where Persistent Connection is disabled for HTML files but other assets like CSS, JS, images, etc. will have Persistent Connection enabled. If you don't have a high volume site you could disable the Smart Keep-Alive feature.