Why are cookies set with `setcookie` starting with a dot?

Question

Example:

<?php
setcookie('test_cookie', '1', time()+3600, '/', $_SERVER['SERVER_NAME']);
echo $_SERVER['SERVER_NAME'];  // outputs: entwicklung.hausfux

Afaik the dot is a wildcard selector.

This causes login problems if you are trying to login into subdomain websites.

Possible duplicate of https://stackoverflow.com/questions/2285010/php-setcookie-domain — Vincent Decaux, May 29 '19 at 10:07
https://stackoverflow.com/questions/9618217/what-does-the-dot-prefix-in-the-cookie-domain-mean — revengeance, May 29 '19 at 10:08
Possible duplicate of [php setcookie domain](https://stackoverflow.com/questions/2285010/php-setcookie-domain) — Zain Farooq, May 29 '19 at 10:08

score 0 · Answer 1 · answered May 29 '19 at 10:15

0

There are the two example for this.

n1.example.com and .n1.example.com

n1.example.com using for domain and .n1.example.com for subdomain. subdomain set dot value. it just use for subdomains as inherit cookies from their parent domain.

answered May 29 '19 at 10:15

Nilesh

97
5

score 0 · Accepted Answer · answered Jun 06 '19 at 10:43

0

I figured out that if you ommit the cookie domain parameter in the setcookie function, then it sets the current domain name without a dot at the start.

setcookie('test_cookie', '1', time()+3600, '/');

answered Jun 06 '19 at 10:43

Black

18,150
39
158
271

Why are cookies set with `setcookie` starting with a dot?

2 Answers2