Problems with Firefox 4 beta and cookies?
August 20th, 2010
Did you experience problems with Firefox 4 beta and cookies? A possible cause is that in Firefox 4 beta, the cookie limit is now per-domain instead of per-host, so any single domain can now, by default, keep up to 50 cookies. For some Web applications. that might be set too low. When the limit is hit, Firefox will start “randomly” deleting cookies, which can cause problems, typically with Web applications that use cookies for Single Sign-on and login credentials.
The solution is to browse to about:config, and add (or modify it if already exists) an integer preference named network.cookie.maxPerHost. Set it to 500 or somesuch. You may or may not want to also set network.cookie.maxNumber (the default is 3000).