How do sessions and cookies work

Home Testing Expand child menu Expand. SAP Expand child menu Expand. Web Expand child menu Expand. Must Learn Expand child menu Expand. Big Data Expand child menu Expand. Live Project Expand child menu Expand. AI Expand child menu Expand. Toggle Menu Close. Search for: Search. Within-session you can store as much data as you like. Note: To see stored cookies and other storage that a web page can use , you can enable the Storage Inspector in Developer Tools and select Cookies from the storage tree.

The browser usually stores the cookie and sends it with requests made to the same server inside a Cookie HTTP header. You can specify an expiration date or time period after which the cookie shouldn't be sent. You can also set additional restrictions to a specific domain and path to limit where the cookie is sent. For details about the header attributes mentioned below, refer to the Set-Cookie reference article.

A simple cookie is set like this:. Then, with every subsequent request to the server, the browser sends all previously stored cookies back to the server using the Cookie header. Note: Here's how to use the Set-Cookie header in various server-side applications:. Note: When you set an Expires date and time, they're relative to the client the cookie is being set on, not the server. If your site authenticates users, it should regenerate and resend session cookies, even ones that already exist, whenever a user authenticates.

This approach helps prevent session fixation attacks , where a third party can reuse a user's session. You can ensure that cookies are sent securely and aren't accessed by unintended parties or scripts in one of two ways: with the Secure attribute and the HttpOnly attribute. It's never sent with unsecured HTTP except on localhost , which means attackers man-in-the-middle can't access it easily. Insecure sites with http: in the URL can't set cookies with the Secure attribute. However, don't assume that Secure prevents all access to sensitive information in cookies.

For example, someone with access to the client's hard disk or JavaScript if the HttpOnly attribute isn't set can read and modify the information. For example, cookies that persist in server-side sessions don't need to be available to JavaScript and should have the HttpOnly attribute.

This precaution helps mitigate cross-site scripting XSS attacks. The Domain and Path attributes define the scope of a cookie: what URLs the cookies should be sent to. The Domain attribute specifies which hosts can receive a cookie.

If unspecified, the attribute defaults to the same host that set the cookie, excluding subdomains. If Domain is specified, then subdomains are always included. An attacker can sniff the cookies, and set it as its own, he won't see the variables themselves, but the server will identify the attacker as the user. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. What are cookies and sessions, and how do they relate to each other? Ask Question. Asked 9 years, 4 months ago. Active 2 years, 6 months ago. Viewed 62k times. Improve this question. Makoto Blanktext Blanktext 1, 2 2 gold badges 12 12 silver badges 16 16 bronze badges. It seems you already know what's happening. Which specific part would you like to be enlightened on?

The cookie that the browser is saving with the phpsessid, is this the phpsessid to identify the client for creating sessions and cookies? Yes i know that, but i am asking, is this "phpsessid" is using to identify the client before creating sessions and cookies, is this phpsessid is including inside the cookie data and the client computer and inside the session file at the server tmp folder? Add a comment.

When you sign in into a site, a token is generated that identify your session. This token is then stored on a cookie, so as long as you keep the cookie and it doesn't expire , you will be signed directly every time you access the site. That's why it's important to delete cookies or better use safe mode when you are on a public PC. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. How session cookies work? Asked 7 years, 1 month ago. Active 7 years, 1 month ago. Viewed 5k times. Improve this question. Anandu M Das. How come this an off topic question?