note 67262 modified in function.setcookie by theseer

I just discovered that IE6 (6.0.2800.1106 at least) seems to have difficulties accepting cookies when the subdomain part of the URL is longer than 10 characters. This applies to automatic sessionid's as well (that's how I found out). So: Setting a cookie on a site named http://examples.test.com/ will work, doing the same on http://my_examples.test.com will fail (or at least, failed for me). Tested it by snooping the outgoing traffic from the client: the GET request lacks the COOKIE: header in the last case. A closer inspection revealed that the cookie was never accepted in the first place: when the subdomain is longer than 10 characters, no cookiefile is created in the temporary internet files directory. Temporary cookies (like the PHP sessionid) have the same problem. Firefox and Konqueror have no problem with this. [Editor's note: Your comment is wrong. It is not the length of the hostname but the use of the underscore (_) char within it which makes IE (silently) freak out. The use of underscores in hostnames is an RFC violation and may very well not be supported at all by a browser, proxy or any http client.] --was-- I just discovered that IE6 (6.0.2800.1106 at least) seems to have difficulties accepting cookies when the subdomain part of the URL is longer than 10 characters. This applies to automatic sessionid's as well (that's how I found out). So: Setting a cookie on a site named http://examples.test.com/ will work, doing the same on http://my_examples.test.com will fail (or at least, failed for me). Tested it by snooping the outgoing traffic from the client: the GET request lacks the COOKIE: header in the last case. A closer inspection revealed that the cookie was never accepted in the first place: when the subdomain is longer than 10 characters, no cookiefile is created in the temporary internet files directory. Temporary cookies (like the PHP sessionid) have the same problem. Firefox and Konqueror have no problem with this. http://php.net/manual/en/function.setcookie.php