Changing permalink settings causes 404

Question

I would like to have permalinks of the form http://localhost/mysite/sample-post/. I tried to achieve this by changing the permalink settings in the admin panel to 'Post name' from default. But this causes 404: page not found error.

I've tried with the other settings e.g., month and name, numeric etc. but all of them results in 404. The generated URL is changing according to the permalink setting though.

Clearing the cache did not help either.

Does something else need doing here ? Thanks.

Edit:

My server: lamp on ubuntu 12.4 lts

Contents of the .htaccess

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /mysite/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /mysite/index.php [L]
</IfModule>

# END WordPress

Answer 1

There are several possibilities: you may need to enable mod_rewrite on the Ubuntu server or check/fix permissions to allow Wordpress to write to the .htaccess file.

Best thing to do is read http://codex.wordpress.org/Using_Permalinks and work through suggestions.