Yann at WP&amp;Co

This plugin has been thoroughly tested and is fully compatible with WordPress 3.0x multisite or with WPMU 2.9.
This plugin was originally named YD WPMU Sitewide Options. The name has been changed with version 3.0 to match WordPress 3.0 vocabulary and concepts. Backwards compatibility with WordPress MU has been maintained.
<h4>Centralized management of your network-wide installed plugins!</h4>
This WordPress 3.0 multisite or WPMU plugin installs a new settings page where you can choose which blog or plugin settings you want to replicate site-wide or network-wide to all your children sites. 
Any change (update) to those settings (options) on the mother site admin pages can be automatically copied to all the sub-sites (blogs).
You can choose which settings to replicate, you can decide if changes of the settings on the main blog should be automatically replicated to all blogs.
You can replicate your settings as a “one-shot” process (for example when setting up new blogs or installing a new network-wide or site-wide plugin), 
or have the plugin maintain your settings in sync on all your blogs over time.
You can decide if chosen settings will be automatically “spread” to newly created blogs or not.
You can choose to manually spread the settings only when you decide to, and not to overwrite existing individual blog settings. 
This way, you can maintain specific settings on some blogs while keeping the ability to spread default settings to new blogs.
Since version 4.0.0, the plugin can now create and copy custom database tables used by some plugins, further widening the scope of plugins that can be made network-wide manageable.
Those techniques can be used to convert any standard WordPress plugin from standalone to a versatile multisite network-wide or sitewide WPMU plugin!
You can use your main blog as a template-blog for the creation of new sites in your network: the new sites can automatically adopt any or all settings of your main blog, 
activated plugins can also be copied, as well as the settings of each plugin. This is an alternative to other commercial or non-commercial new blog defaults / new blog template plugins for WPMU.
Many other creative uses are possible.
It efficiently makes for a centralized deployment of any plugin parameter on all your WPMU blogs: the main blog acts as a “master” when setting the site-wide option, while your child blogs replicate any change in the option over time like “slaves” (a rather typical master-slave replication pattern).
The plugin has its own admin options page (settings page).
It is fully internationalized.
Base package includes .pot file for translation of the interface, and English, French, Dutch and German versions.
<h4>Compatibility</h4>
This plugin has been successfully tested to convert the following standalone WordPress plugins to network-wide Worpress 3.0x multisite or sitewide WordPress MU plugins with centralized administration:
<ul>
<li>All WordPress core-options including WordPress 3.0x default theme header options, active plugins, administrator e-mail, commenting otpions and search engine accessibility (public/private status), etc.</li>
<li><a href="http://WordPress.org/extend/plugins/akismet/" rel="ugc">Akismet plugin</a> credentials (API Key)</li>
<li><a href="http://WordPress.org/extend/plugins/yd-spread-parameter/" rel="ugc">YD Spread Parameter plugin</a></li>
<li><a href="http://WordPress.org/extend/plugins/yd-export2email/" rel="ugc">YD Export2Email plugin</a></li>
<li><a href="http://WordPress.org/extend/plugins/wp-theme-switcher/" rel="ugc">WP Theme Switcher plugin</a></li>
<li><a href="http://WordPress.org/extend/plugins/dj-email-publish/" rel="ugc">DJ E-mail Publish plugin</a></li>
<li><a href="http://wprobot.net/" rel="nofollow ugc">WPRobot plugin</a> credentials and settings</li>
<li><a href="http://WordPress.org/extend/plugins/easy-privacy-policy/" rel="ugc">Easy Privacy Policy plugin</a></li>
<li><a href="http://wpmu.org/plugin-commander-111/" rel="nofollow ugc">WordPress plugin Commander</a> to centrally activate or de-activate plugins network-wide</li>
<li><a href="http://wpml.org/" rel="nofollow ugc">WPML Multilingual CMS</a> (new since version 4.0.0)</li>
<li>and many, many more…</li>
</ul>
Only some plugins that do not use either WordPress’ built-in options mechanism or some simple database tables to store their settings cannot be made network-wide with this plugin. 
However, the vast majority of state-of-the art third-party plugins use options and/or simple tables.
Please leave a comment on the <a href="http://www.yann.com/en/wp-plugins/yd-wpmu-sitewide-options" title="Yann Dubois' Network-wide options plugin for multisite WordPress" rel="nofollow ugc">support site</a> to report 
other successful implementations, or any incompatibility.
<h4>Active support</h4>
Drop me a line on my <a href="http://www.yann.com/en/wp-plugins/yd-wpmu-sitewide-options" title="Yann Dubois' Network-wide options plugin for multisite WordPress" rel="nofollow ugc">WordPress developer site</a> to report bugs, ask for a specific feature or improvement, or just tell me how you’re using the plugin.
<h4>Description en Français :</h4>
Ce plug-in pour WordPress 3.0x multi-site ou WordPress MU permet de recopier automatiquement n’importe quel paramétrage (option, réglage) de plugin sur tous les blogs de votre réseau WordPress 3.0x ou WPMU. 
Toute modification (mise à jour) faite sur un paramètre sélectionné dans le blog principal peut être automatiquement répercutée sur les sous-blogs. 
De cette façon, vous pouvez centraliser la gestion de vos plugins transversaux.
Avec cette technique, n’importe quel plugin WordPress standard peut être converti en un plugin transversal pour WP3.0x multisite ou WPMU !
Les réglages de vos plugins sont automatiquement déployés sur tous vos sites WP MU ou sur tous les sites de votre réseau multi-sites.
Très pratique si vous installez un plugin transversalement (network-wide) sur tous vos blogs.
Le plugin a sa propre page d’options dans l’administration. 
Il est entièrement internationalisé.
La distribution standard inclut le fichier de traduction .pot et les versions française, anglaise, hollandaise et allemande.
Le plugin peut fonctionner avec n’importe quelle langue ou jeu de caractères.
Pour toute aide ou information en français, laissez-moi un commentaire sur le <a href="http://www.yann.com/en/wp-plugins/yd-wpmu-sitewide-options" title="Yann Dubois' Network-wide Options for multisite WordPress" rel="nofollow ugc">site de support du plugin YD WPMU Network-wide Options</a>.
Yann dubois, <a href="http://www.yann.com/fr/a-propos/developpeur-wordpress" title="Développeur WordPress freelance à Paris" rel="nofollow ugc">Développeur WordPress</a>.
<h4>Funding Credits</h4>
Original development of this plugin has been paid for by <a href="http://www.wellcom.fr" title="Wellcom" rel="nofollow ugc">Wellcom.fr</a>. Please visit their site!
Additional development was paid for by <a href="http://bossinternetmarketing.com/" title="bossinternetmarketing.com" rel="nofollow ugc">Matt Hardy</a>. Please visit his site!
Additional development was paid for by <a href="http://www.eurospreed.com/" title="Eurospreed.com" rel="nofollow ugc">Eurospreed</a>. Please visit their site!
Le développement d’origine de ce plugin a été financé par <a href="http://www.wellcom.fr" title="Wellcom" rel="nofollow ugc">Wellcom.fr</a>. Allez visiter leur site !
Des développements additionnels ont été financés par <a href="http://bossinternetmarketing.com/" title="bossinternetmarketing.com" rel="nofollow ugc">Matt Hardy</a>. Allez visiter son site!
<h4>Translation</h4>
If you want to contribute to a translation of this plugin, please drop me a line by e-mail or leave a comment on the <a href="http://www.yann.com/en/wp-plugins/yd-wpmu-sitewide-options" title="Yann Dubois' Network-wide Options plugin for multisite WordPress" rel="nofollow ugc">plugin’s page</a>. 
You will get credit for your translation in the plugin file and this documentation, as well as a link on this page and on <a href="http://www.yann.com/" rel="nofollow ugc">my developers’ blog</a>.
Dutch version kindly provided by <a href="http://www.fethiyehotels.com" rel="nofollow ugc">Rene</a>
German version kindly provided by <a href="http://www.pangaea.nl/diensten/exact-webshop" rel="nofollow ugc">Rian</a>
<h3>Plugin settings/options page</h3>
Use the plugin’s own settings page to select which plugin options/settings to automatically replicate network-wide / site-wide.
<h3>Revisions</h3>
<ul>
<li>0.1.0 Original beta version.</li>
<li>0.1.1 Optional debug code.</li>
<li>0.2.0 Bugfixes + improved settings page.</li>
<li>1.0.0 Bugfixes + important new features.</li>
<li>1.1.0 Bugfixes + new features.* 1.1.</li>
<li>1.1.1 Bugfix</li>
<li>3.0 WordPress 3.0 compatibility</li>
<li>3.0.1 Minor text changes</li>
<li>4.0.0 Database table replication, bugfixes, flush rewrite rules, choose master, ignore blogs</li>
</ul>
<h3>Did you like it?</h3>
Drop me a line on http://www.yann.com/en/wp-plugins/yd-wpmu-sitewide-options
And… please rate this plugin –>

YD Network-wide Options

This plugin has been thoroughly tested and is fully compatible with WordPress 3.0x multisite or with WPMU 2.9.

Van Patten Media

Designed to be run in concert with <a href="https://wordpress.org/extend/plugins/ssl-subdomain-for-multisite/" rel="ugc">SSL Subdomain for Multisite</a>.
This plugin depends upon <a href="https://wordpress.org/extend/plugins/wordpress-mu-domain-mapping/" rel="ugc">WPMU Domain Mapping</a>, which must be installed and network activated for this to work.
<h4>What this Plugin does</h4>
If you have the <a href="https://wordpress.org/extend/plugins/ssl-subdomain-for-multisite/" rel="ugc">SSL Subdomain for Multisite</a> plugin installed and network activated, you now have logins and admin happening on <code>https://demo-site.mynetwork.com</code>, while normal site access is on <code>http://demo-site.com</code>.
This works great. Except, once you log in to <code>demo-site.mynetwork.com</code> to do some admin work, then visit the main site, perhaps to post a comment as a logged in WordPress user, you are not logged in on the main site. This means that you can’t, for example, post that comment while logged in — you aren’t logged in there! Other logged-in niceties like the display of the admin bar, or the avoidance of caching, are not available. If you log in again, it logs you in to <code>https://demo-site.mynetwork.com</code> but still you remain not logged in on <code>http://demo-site.com</code>.
This plugin solves this problem by enabling a single sign on (SSO) for both the admin panel and the main site on the custom domain. Upon login, this plugin bounces the user across to the main site to set a cookie there, then bounces them back to the admin panel.
Now, you can work in the admin panel normally, and if you click ‘Visit Site’ from the Admin panel, you go over to the custom domain, where you are also logged in and can perform all actions as normal. Single Sign On!
<h4>(Foolish) Assumptions</h4>
<ol>
<li>
You are using <a href="https://wordpress.org/extend/plugins/wordpress-mu-domain-mapping/" rel="ugc">WPMU Domain Mapping</a> for custom domains on your Multisite network.
</li>
<li>
You have SSL configured for your master domain (e.g. <code>www.mynetwork.com</code>), and for the wildcard <code>*.mynetwork.com</code>. You would like normal site access to happen over the custom domains with HTTP, and all admin and login access over the subdomains of <code>*.mynetwork.com</code> with HTTPS.
</li>
<li>
You have the <code>FORCE_SSL_LOGIN</code> setting in <code>wp-config.php</code> ON.
</li>
<li>
You have the <code>FORCE_SSL_ADMIN</code> setting in <code>wp-config.php</code> OFF. We’ll handle that — WordPress’ forcing of SSL admins may confuse this plugin.
</li>
</ol>
This plugin was tested with and is intended to be used in concert with <a href="https://wordpress.org/extend/plugins/sso-cross-cookie-for-multisite/" rel="ugc">SSL Subdomain for Multisite</a>.
<h4>Known Issues</h4>
<ul>
<li>The <code>redirect_to</code> parameter is not fully working at present. Sometimes, you will be sent to the root admin page, instead of the specific page you were trying to access. This needs to be improved, as it does compromise the user experience.</li>
<li>
This provides better security than only enabling <code>FORCE_SSL_LOGIN</code> but not <code>FORCE_SSL_ADMIN</code>, since with this plugin and <a href="https://wordpress.org/extend/plugins/sso-cross-cookie-for-multisite/" rel="ugc">SSL Subdomain for Multisite</a>, login and admin are served over HTTPS.
However, the nature of this setup means that a man-in-the-middle attacker could theoretically impersonate you for the duration of the login session. It is not possible at the moment to avoid this theoretical attack scenario without serving everything over HTTPS (making arbitrary custom domain support impossible), or preventing login to the actual custom domain site.
</li>
</ul>

SSO Cross Cookie

Single sign on (SSO) for a custom domain site, where the admin panel is on an SSL-secured subdomain. For WordPress Multisite.

YD Network-wide Options vs SSO Cross Cookie