Is there a way to Network Administrators for disabling firefox extensions installing?

Question

Could we disable firefox extensions installing for non-admin users?

Answer 1

Sort of. You can apply lock down settings with mozilla.cfg. This, however, will prevent all users from using locked down features though. Administrators can of course swap in/out the config file at will.

http://www.pcc-services.com/kixtart/firefox-lockdown.html

Edit: Here's the list of settings we deploy via lock down. It's a K-12 environment, so your needs will likely vary.

//
lockPref("app.update.auto", false);
lockPref("app.update.enabled", false);
lockPref("app.update.silent", true);
lockPref("browser.cache.disk.capacity", 1000);
lockPref("browser.download.useDownloadDir", false);
lockPref("browser.rights.3.shown", true);
lockPref("browser.search.update", false);
lockPref("browser.shell.checkDefaultBrowser", false);
lockPref("extensions.update.enabled", false);
lockPref("plugin.default_plugin_disabled", false);
lockPref("plugin.scan.plid.all", true);
lockPref("plugins.hide_infobar_for_missing_plugin", true);
lockPref("profile.allow_automigration", false);
lockPref("signon.prefillForms", false);
lockPref("signon.rememberSignons", false);
lockPref("startup.homepage_override_url", "");
lockPref("startup.homepage_welcome_url", ""); 
lockPref("xpinstall.enabled", false);
lockPref("xpinstall.whitelist.required", true);

EDIT:

I am adding a link to the official Mozilla.org docs regarding locked config settings.

If the information I have provided does not answer your question well enough, please provide additional information describing your needs.