Change record status: 
Project: 
Introduced in branch: 
8.x
Introduced in version: 
7.9
Description: 

The example $cookie_domain variable in default.settings.php failed for sites with subdomains and did not meet RFC 2109 standards. When $cookie_domain contains only one dot, each subdomain like http://de.example.com and http://fr.example.com issues its own session cookie to the user which prevents the session remaining active when switching between domains.

Old implementation:
$cookie_domain = 'example.com';

Correct version:
$cookie_domain = '.example.com';

The patch corrects both the documentation of this functionality and the example given in default.settings.php.

Impacts: 
Site builders, administrators, editors
Updates Done (doc team, etc.)
Online documentation: 
Not done
Theming guide: 
Not done
Module developer documentation: 
Not done
Examples project: 
Not done
Coder Review: 
Not done
Coder Upgrade: 
Not done
Other: 
Other updates done